Architecture at ZSL London Zoo, Regent's Park

In 1826, Stamford Raffles together with Humphry Davy brought together a group of scientists, collectors, gentry and gentlemen and founded the Zoological Society of London. The purpose of the Society was to form a collection of animals and study them for the advancement of zoological knowledge. The Society obtained a lease on an area of Regent's Park in 1826 and appointed Decimus Burton, a young architect, to lay out the gardens and design accommodation for the animals.

From its beginnings it was an integral part of this area of London. Its architecture blends into Regent's Park and allows the public to see exotic creatures right in the centre of the city.

Over almost 200 years many leading architects have contributed to the built environment of ZSL London Zoo. It has developed with a wealth of architectural variety that illustrate trends and styles in architecture and methods of construction over that period. The collection of buildings has such architectural interest that it includes two Grade I and eleven Grade II listed structures and there is nowhere else in the UK that has so many listed structures of such diversity in such a small area. They represent two centuries of architectural history and demonstrate the challenge in designing to meet the needs and requirements of the natural world and man's interest and relationship with it.

The architecture also illustrates the history of animal husbandry. The known requirements for looking after animals properly has developed from a literal blank page in the early 19th century where animals were often being seen for the first time. Today, cooperation with research and information regarding best husbandry practice, from across the world, allows this knowledge to be incorporated in the design of each new enclosure.

Such a legacy of listed architecture within the Zoo means it has had to adapt. Some buildings are considered to be obsolete and unsuitable for their original function. The Zoo has amended some of the buildings to get the optimum use from the structures to best suit the requirements of the animals as we know them to be today.

Here we examine how the Zoo has developed and highlight the history and background to the key buildings that exist today.

The First 10 Years

The Zoo opened to the Fellows of the Zoological Society and their friends on 27th April 1828. The zoological gardens as they were then called, were a work-in-progress with construction work continuing through the early years. Some of the permanent structures were significant and still exist in the Zoo today.  

Clock Tower / Llama & Camel House

1828 designed by Decimus Burton. Listed Grade II.

Photo - ZSL London Zoo's Clock Tower at dusk

The earliest original building in the Zoo, the Llama House was designed by Decimus Burton in 1828. In 1829 it was 'ordered' that a clock be prepared for the Gardens to be placed on top of the Llama's hut and that Decimus Burton be requested to prepare a drawing of the intended addition to the building. The clock was added in 1831. The clock tower was redesigned and rebuilt in its current form in 1844.

It suffered, like other parts of the Zoo, from bomb damage in 1940 and was rebuilt in 1946-7 by the architects Burnet, Tait & Lorne. In 1988 it was converted into shops and now serves as a First Aid post. 

The Raven's Cage

1828 designed by Decimus Burton. Listed Grade II.

This is the first permanent cage to have been erected in the Zoo. It is octagonal in plan and was originally designed to house macaws, later vultures and ravens. It was renovated in 1927 and bomb damage led to it being reconstructed in 1948. It was moved in 1971 to its present site on the Members' Lawn. It is one of the icons of the Zoo.

East Tunnel 

1829-30 designed by Decimus Burton. Listed Grade II.

This simple construction linked the North and South parts of the Zoo, on either side of the Outer Circle, for the first time. The original entrance portal to the south survives, the other was demolished as part of the construction of the Institute of Zoology in 1964. It is the only building in the Zoo that follows the classical style of the Regents Park buildings designed by John Nash. During World War II it served as a bomb shelter.

Three Island Pond

1832 designed by Decimus Burton.

This irregularly shaped artificial pond is the only landscaping to remain from the early gardens and was designed by Decimus Burton. The ponds have been remodeled on several occasions, the last as part of the Land of the Lions in 2016.

The islands are now planted with large willows and are populated by pelicans and flamingos. 

Giraffe House

1836-7 designed by Decimus Burton. Listed Grade II.

This building is simple, utterly functional and still serves its purpose – it houses giraffes. It was built specifically for the arrival of the Zoo's first giraffes. The suitability of the design is illustrated by the breeding success when 17 fawns were born between 1839 and 1867 

The doors are 5m high and the building 6.5m at the eaves. Giraffes can be as tall as four-and-half meters, so the scale of the building's proportions is a direct response to the height of its residents. 

The Giraffe house is one of the oldest zoo buildings in the world still being used to house its originally intended inhabitants. Wings were added to the building in 1849-50 to accommodate hippopotamus and zebra. 

There was bomb damage in 1940 which led to the escape of a zebra. Franz Stengelhofen and Peter Shepheard incorporated it the Cotton Terraces redevelopment in 1960-3 where new buildings and paddocks were constructed around the original.

The Victorian Years

The Zoo developed through the 19th Century with extensive new construction. The buildings were generally of functional design, many of brick and typical of the period. The Zoo broke new ground through this period with some notable 'firsts' in world zoo history with the first ever Reptile House, Aquarium (originally an 'Aquaviverium') and Insect House. 

The Lion House, Monkey House, Carnivore Terrace and Elephant and Rhino House were all significant structures with the Lion House staying in use for 100 years up until 1975. These buildings have been demolished to reflect changing requirements and only three buildings of note have survived.

Eastern Aviary    

1863 designed by Anthony Salvin Jnr.

Now known as the Birds of Prey Aviary. It was extensively reconstructed in 1989 in the same form as the original with a hooped tubular steel frame and strained 'invisible' wire to enclose the space. The original bird housing is still in use and remains visible at the back of the enclosure. 

Blackburn Pavilion (Formally Reptile House)    

1882 designed by Charles Brown Trollope.

The Blackburn Pavilion was originally the second reptile house to be built in the Zoo. It was converted to a bird house in 1927 with the addition of external aviaries. The original classical design can be seen in the balustrade and lead clad cupola at roof level. There were originally four cupolas, one at each corner of the building.

The building was extensively refurbished in 2008 and many Victorian features have been brought back to their original appearance and a feature clock added at the entrance. The clock is by Tim Hunkin, artist and designer of automaton. The clock springs to life on the hour and half hour.

Stork and Ostrich House    

1896 designed by Charles Brown Trollope.

The original structure which originally provided 28 enclosures for large birds has been adapted and is now included within Tiger Territory, the African Aviary and the Galapagos Tortoise exhibits.

A New Century 

At the beginning of the 20th Century there was a new mood in Zoos around the world and with the appointment of Peter Chalmers-Mitchell as Secretary, ZSL was no exception. He was elected in 1903 and set the Zoo on a path for change. He sought the most modern thinking in Zoo design and from his appointment to his retirement in 1935 he challenged thinking about animal husbandry. He was also the prime influence behind the development of Whipsnade Zoo.

ZSL Offices and Library

1909-10 designed by John James Joass.

This building was built to facilitate a move from Hanover Square, to create better access to the Zoo and to accommodate a growing collection of books. The interior of the ZSL Library was extensively remodeled in 1965 by Franz Stengelhofen and Colin Wears.

Mappin Terraces

1913-4 designed by Sir Peter Chalmers Mitchell and John James Joass. Listed Grade II.

The four artificial mountains of the Mappin Terraces are the Zoo's largest and most prominent feature. The panoramic design was derived from the work of Carl Hagenbeck in Hamburg Zoo. It was built on additional land that was given to the Zoo on the condition that any exhibit would face into Regents Park so that its inhabitants could be seen by the public.

This extraordinary imitation of a mountain landscape was designed to provide a naturalistic habitat for bears and other animals. There are three levels where boundaries between them are invisible from the viewing platform in front of the Mappin Pavilion. The construction of the terraces was unconventional and illustrated what could be achieved with reinforced concrete. The internal structure that supports the terraces and creates the shapes is extremely complicated and the whole design utilises technology developed for industrial factories in the USA. 

War Memorial

1919 designed by John James Joass. Listed Grade II.

The war memorial was erected in 1919 recording the employees of ZSL who died in the first World War and was updated adding those employees lost in the Second World War. It was moved to its current location by the Three Island Pond in 1952. The design is taken from the medieval French Lanterne des Morts at La Souterraine in the Creuse valley. 

Mappin Pavilion

1920 designed by John James Joass. Listed Grade II.

Photo - Wide-angle view of the exterior of the Mappin Pavilion on a sunny day

The Mappin Tea Pavilion, built in an Italianate style, were part of the original terraces design, but their construction was delayed until after World War One. 

Pavilion Building

1921-22 designed by John James Joass. 

This building continues the Italian Renaissance style. It was originally a tea-room. It now houses the main retail area and the exit route from the Zoo.


1924 designed by John James Joass. 

The space for the Aquarium was provided in the design of the Mappin Terraces although its construction was postponed until ten years after the terraces were opened, delayed by the war and funding. The design incorporated large storage tanks and filter beds under the Terraces. The façade on the public face of the building is finished in a classical style of the 1920's. 

Behind the facade the building is a simple functional design with wide public circulation areas and more than 100 tanks around the perimeter. Back of house areas are at a higher level to provide access to the tanks. The tanks were originally built with 50mm slate slabs faced with glass to the public areas.

Unfortunately, the structure has come to the end of its useful life and its future is being considered as part of new plans for the Zoo. It was closed in 2019.

Reptile House

1926-7 designed by Joan Beauchamp Procter and Sir Edward Guy Dawber.

In 1849 London opened the first reptile house in the world. The current building is the third Reptile House and replaced a building of 1882-3, (Now the Blackburn Pavilion). Built in an Italianate style, complementing the Mappin Pavilion, it was hailed as the most sophisticated building of its type in the world when it opened. 

The building was designed to a meticulously considered brief thanks to the Reptile Curator of the time, Joan Procter. It incorporated differential heating and 'aquarium principle' lighting, whereby the public spaces are purposely dark to highlight animals in landscaped exhibits. Carved reptiles and other animals by George Alexander climb around the entrance doors.

Regent Building

1928-29 designed by John James Joass. 

This building was built to provide improved restaurant facilities. It is of a simple design without the Italian ornamentation of other buildings of the time. The restaurant and internal space were extensively refurbished and extended in 2013.

K3-type telephone kiosk 

1928-9 designed by Giles Gilbert-Scott. Listed Grade II.

Gilbert-Scott, the architect of Battersea Power Station designed the K2 telephone box in 1924 for a competition, but his second design, the K3 was made from reinforced concrete at half the price of the cast-iron K2. This has now been repainted in its original colours.

Gorilla (Round) House

1932 designed by Tecton. Listed Grade I.

Photo - Old black and white photo of the Round House

The Round (Gorilla) House is one of the first buildings to be built in the Modernist style in Britain and was designed by Russian émigré Berthold Lubetkin a member of the Tecton Group. Lubetkin and Tecton went on to design many zoo buildings, some here at London and at Whipsnade, together with Dudley Zoo in the Midlands. It was a bold step to introduce this new style of architecture which sought to present the animals to the public in a dramatic manner

The brief for the building required convertible open caging to allow the gorilla's fresh air in the summer and access to view the animals inside for the public in winter. The design was circular so that a half-drum steel and timber shaped screen could be rotated from within one half of the building to enclose the other in the winter. The cogs that enabled this structure to be moved are still visible. Other original features include the use of aerated concrete in the structure as insulation and an air-conditioning system that recreated the moist warm conditions of the rainforest.

It proved to be unsuitable for large apes and was converted to house elephants in 1939. It has been used for a variety of purposes since then, most recently with Fruit Bats.

Penguin Pool

1934 designed by Tecton. Listed Grade I.

The Penguin Pool is perhaps the most famous building in the Zoo. It was also designed by Berthold Lubetkin of Tecton. They were given the commission for the design following the enthusiastic reception of the Gorilla (Round) House. 

Lubetkin was given liberty to design an exhibition piece, a non-naturalistic stage for the antics of the penguins that avoids any appearance of caging. The design is an influential and popular piece of early modernist architecture and superb engineering formed entirely with reinforced concrete. The engineering design was led by Ove Arup as one of his first commissions. Its elegant and playful style appears as innovative and interesting today as when it first appeared. It is unfortunate that it no longer suits the requirements for keeping penguins.

North Gate Kiosk 1936

1936 designed by Tecton, listed Grade II.

A further commission for Tecton following on from the Penguin Pool and Gorilla House. It has an unusual wave form reinforced concrete canopy, another example of how Tecton pushed the boundaries in this emerging form of construction. NB this is not accessible owing to the Snowdon development work.

The New Zoo

Following the Second World War the Zoo carried out the repairs that were necessary and in the early 1950's as visitor numbers started to rise, ZSL started to look at a major reconstruction of the Zoo. A plan was developed by Franz Stengelhofen (the Zoo's architect) and later with Hugh Casson and was published in 1958. Following a major fund-raising exercise, it led to the most intensive period of construction in the Zoo's history. 

Several of the buildings constructed in this period have been incorporated into more recent enclosures notably The Michael Sobell Pavilions (1972), constructed to house the Zoo's apes and monkeys, now part of Gorilla Kingdom and the Lion Terraces (1975), now part of Land of the Lions. The following buildings remain in their original form:

West Footbridge

1960-61 by Sir Hugh Casson, Neville Conder & Partners. Listed Grade II.

The bridge was built to improve the links between the North and Middle Gardens as part of the Cotton Terraces redevelopment and is formed from precast and post-tensioned concrete. Different aggregates have been used in the concrete components; these are exposed to create a distinctive contrasting coloured finish.

The Cotton Terraces    

1960-63 designed by Peter Shepheard and Franz Stengelhofen.

The first major construction arising from the 1958 masterplan. A lower terrace was created alongside the canal with accommodation for the deer and antelope it was to contain. Above this on the upper terrace two new animal buildings were constructed either side of the 1836 Decimus Burton Giraffe House and are designed to be in keeping with it. 

The terraces now house part of the 'Africa' exhibit including giraffes in their original building, almost 200 years on.

Snowdon Aviary

1962-4 designed by Tony Armstrong-Jones (Lord Snowdon), Cedric Price and Frank Newby. Listed Grade II*.

Photo - A view of the Snowdon Aviary with trees in the background and the canal in the foreground
Snowdon Aviary, ZSL London Zoo, 2015

This enclosure is one of the first large walk-through aviaries ever built. The frame was pioneering in that it made use of aluminum structural members and used tension to support its structure. A net of anodised aluminum wire is wrapped around steel cables on a skeleton of poles. There are paired diagonal 'sheer legs' at either end each linked to two three-sided pyramids or 'tetrahedrons' 
The zig-zag walkway through the aviary is partially cantilevered out into the space over the canal bank which is cut away and terraced with reinforced concrete retaining walls forming a cliff with nesting holes. There is an internal water system with a fast-flowing east waterfall over faceted concrete and a slower west waterfall stepped over basins, which form small ponds for water birds.

The Aviary is currently subject to a major reconstruction.

Casson Pavilion (The Elephant and Rhino Pavilion)

1962-5 designed by Sir Hugh Casson, Neville Conder and Partners. Listed Grade II*.

As heavy and solid as an elephant, in contrast to the Snowdon Aviary that was being built at the same time, it is a 'brutalist' concrete structure topped with tall copper covered ventilation and lantern towers. The texture of the hand hacked concrete which forms the external façade of the building emulates the skin of the animals it was designed to hold. From a distance it gives the impression of elephants gathering around a waterhole.

Visitors no longer have access to the interior. Internally the building is cavernous, it is split into pens around the perimeter that held the individual rhino and elephants, each pen lit by the lanterns above. The former public area features concrete benches and barriers and a central timber frame that echo the scale and form of the exterior. All ZSL's elephants and rhinos now live in more spacious and appropriate accommodation at Whipsnade Zoo.

ZSL Meeting Rooms and Nuffield Building

1964 – 65 by Llewelyn-Davies, Weeks and Musgrave.

This forceful example of Brutalist architecture houses The Institute of Zoology and is a world-renowned research centre working at the cutting edge of conservation biology, specialising in scientific issues relevant to preserving animal species and their habitats. 

The lower levels of the building are constructed in structural concrete and this design continues inside into the public areas of the building. The higher levels are clad in precast panels with a coarse aggregate finish. 

Charles Clore Pavilions    

1970-72 designed by JW Toovey.

Part of the 1958 plan was the Charles Clore Pavilion for Mammals. It is a brick building formed of irregular shaped blocks with a series of indoor, small enclosures. The basement, originally constructed as part of a proposed elephant house, contains 'Night Life' where day and night are reversed by artificial lighting. An area has also been used to create 'Rainforest Life' a walk-through experience with animals and planting illustrating the rainforest environment.

The 21st Century

Following the period of intensive construction between 1960 and 1975 there was little new development in the Zoo until the beginning of the new century. A series of redeveloped enclosures were planned which began to see more space being given to individual species. Each new exhibit incorporates design that encourages immersion in the experience and learning and gaining awareness of the conservation work that ZSL carries out across the world. The major projects have been: 


1997-99 designed by Wharmby Kozdon Associates.

B.U.G.S! (Biodiversity Underpinning Global Survival) is held in a building called The Millennium Conservation Centre and aims to educate the public about biodiversity. There are over 140 species kept in BUGS!, the vast majority of which are invertebrates. 'Web of life' was the name of the exhibit when it was opened by HM The Queen in 1999.

The Millennium building is environmentally friendly, constructed from materials requiring little energy to produce. It generates most of its heat from the exhibits, the sun through the large areas of glass and the body heat of the visitors. It is cooled by air circulation and geo-cooling from pipes 40m below the ground. A key feature of the building is that it is a flexible space that can be adapted over time to suit changing requirements and knowledge of animal welfare.

In 2020 it will open a new exhibit about corals and the conservation threats to coral reefs.

Gorilla Kingdom

2006-7 designed by Proctor & Matthews.          

This lightweight structure and landscaped exhibit was completed in 2007. It gives the gorillas a large open space and natural environment surrounded by a moat on three sides - a significant difference to the 1932 Gorilla House. The enclosure presents a variety of viewpoints of the gorillas as the visitors follow the path around the enclosure and into the enclosed viewing area. 

The design of the viewing area echoes the materials and culture of the natural habitat of the gorillas in the Congo and Rwanda. The design also retains some of the previous 1972 Michael Sobell Pavilion ape and monkey houses with their distinctive space frame external enclosures.

Penguin Beach 

2011 designed by Wharmby Kozdon Associates.

Penguin Beach recreates a sand and pebble beach landscape with a colony of Humboldt penguins. The exhibit's 1200 square metre pool is four times bigger and three times deeper than the Zoo's old penguin pool and holds 450,000 litres of water. 

The design and the use of modern materials and structures in the exhibit mean that close encounters with the penguins are possible and there are stunning underwater viewing opportunities.

Tiger Territory 

2012-13 designed by Wharmby Kozdon Associates.

The Tiger Territory exhibit is formed by a light steel net that encloses a space of 2,500 sq m, five times greater than the previous tiger enclosure on the Lion Terraces. The enclosure encompasses two significant original buildings; the stork and ostrich house and the sea lion viewing platform. 

The steel mesh which is formed with 3mm steel cable is stretched into its circus tent style by four black poles (up to 20m high). There are two enclosures within one which allow separation of male and female tigers - the division being formed with a glazed wall. The walk around the enclosure is an immersive experience and allows viewing of the animals at different levels in a natural landscape.

Land of the Lions

2015/16 designed by Ray Hole Architects.

Photo - A colourful Indian themed marketplace replica with brightly painted shops and stalls

The design of this exhibit recreates India's vibrant Sasan Gir in Gujarat, the last remaining stronghold of Asiatic lions and demonstrates how the lions' natural habitat overlaps with the local urban environment. 

The 2,500 square metre exhibit is constructed around the 1975 Lion Terraces and has introduced walkways, some at high level, through all areas of the previous structure to give many different viewpoints of the animals and through a range of urban and rural Indian inspired landscapes and settings including a train station, crumbling temple, high street and guard hut. 

The exhibit is also home to a troop of Hanuman langurs and a band of dwarf mongoose. 

The Future

As ZSL approaches its 200th anniversary it is set to meet the challenges of the modern world and drive towards its vision of 'A world where wildlife thrives'. 

London Zoo is a key part of the strategy to achieve these aims continuing to inspire and inform visitors and provide unrivaled connection to wild animals and their stories in the centre of one of the world's major cities. 

Text mainly by Paul Wilson BSc (Hons), FRICS.

Please note that there are also many sculptures on the site. Details of all sculptures can be found as 'art works' in ZSL Library's online catalogue.