THE METAMORPHOSIS OF THE GREAT ROCK
The Great Rock was created during the major reconstruction of the Zoo between 1909 and 1912, based on the specialist instructions of the Zoo Construction Committee in the capital. The zoological tasks were supervised by the director of the zoo at the time, Dr Adolf Lendl, and the construction technology aspects by Dr Kornél Neuschloss. The primary purpose of the artificial rock was to help the Zoo, that already operated on a overly tight area, appear larger and provide greater space. Thus instead of the completely flat area, with the vertical elevation, a divided and at the same time larger surface would be created with the latest and most spectacular animal runs of the time.
The artificial rock as a zoo rehabilitation concept
The prototype for the artificial rocks were presumably the market booths fabricated from log frames, and covered by cliff effect canvas that served as the scenes for animals and showmen. The first occurrence of the concept of animal friendly artificial rocks, constructed from more permanent structures, was during the development of the Zurich Zoo. The idea according to the records could have come from a sculptor by the name of Urs Eggenschwiler. Although the plan was not realised in Zurich, the director of the Hamburg-Stellingen Zoo, Karl Hagenbeck, jumped at it. The panoramic display later became an example for great zoo constructions of the era, thus the Budapest concept also subsisted on this very same prototype, which in the end surpassed Stellingen. (The Hungarian Committee during its many study tours also visited Stellingen). Today – from the artificial rocks that have survived – the Great Rock of Budapest, with its architectural and sculptural achievement represents an outstanding architectural heritage, with only the Vincennes Zoo of Paris being a match for it in its genre.
The Hungarian Committee carried out a rather thorough preparatory work: several natural scenes were examined for the shaping of the artificial rocks, as well as seeking the opinion of the Magyar Királyi Földtani Intézet (Hungarian Royal Institute of Geology). The dolomite peak of the Great Rock in the shape of a limestone range, was in the end constructed based on detailed surveys and photo documentation of the “Egyeskő” peak in Transylvania; it covered an area of 4,700 m2, with a volume of 38,850 m3 and a height to the peak of 34 m. The plans were prepared by Gyula Végh, and during the three years of construction, 8,000 m3 of concrete was used by the company of György Pohl. The rock crust itself was made from a 6-12 cm thick Portland cement wire lattice structure by the same extraordinarily skilled rock carving and building architect artisans who created the façade decorations of eclectic Budapest; their work being supervised by geologists and sculptors. (The patterned rock cracks also hide the dilatation gaps of the structure).
A hundred year old dormant dream
The well-grounded question of whether it is an overly big extravagance in the altogether ten hectares area of the Budapest Zoo (one of the smallest amongst the zoos of the European cities) not to use or almost not to use such an area under the rock arose even during the construction of the rock. Adolf Lendl wrote about this in his concept of the zoo:
“The entire large hill will be made of cement concrete and will be empty inside. We will open the wall on one of the sides with a cave like gate entrance enclosing it with a light structure, and in the inside a huge hall, this could even be 30 m long. We will erect a stuffed whale here from the northern seas, perhaps together with the skeleton, and also several specimens of dolphins, as these are not expensive and are very characteristic animals that can rarely be seen".
However, a lack of money and the outbreak of World War I washed away the grand dreams of the Zoological Museum. Although there were a few attempts between the two wars for some sort of functional use of the space (e.g.: skating rink, shooting gallery, riding school), mostly it operated as hay storage and junk room, as well as a practice hall for horse trainers until recent times. Over time, the permeability of the crust to water increased, water found its way in and due to the large fluctuations of temperature in the internal space, condensation was continuous, further damaging the condition of the wire lattice structure. Large pieces split from the crust of the artificial rock, thus to prevent accidents a safety steel mesh was stretched onto the reinforced concrete frame.
The reconstruction works, from the surveying to the structural reconstruction of the rock to the complete renewal of the inner space, were coordinated by the architect studio of Péter Kis. Between 2006 and 2008, both the framework and the external covering of the Great Rock were renewed. However, just as one hundred years ago, it seemed that the full utilisation of the space inside the rock would come to a halt yet again due to financial reasons. Although a 3D cinema did start up in the domed hall in 2009, the great dream of Lendl, today’s version of the Zoological Museum seemed to be lost once more due to a lack of funds. Fortunately, and thanks to European Union aid sources and countless innovative ideas, the interactive life museum, the Magical Mountain was finally realised in the Great Rock.
Innovation in the deep
In order for the reconstruction design to commence at all, this huge amorphous structure had to be surveyed, as no exact plans and geodesics were available. It was Dr András Tokody and his team appointed to carry out the survey, who proved to be a direct hit for this task. The versatile surveyors – who had to be IT professionals, industrial alpinists and cave researchers all in one – had to carry out their survey in minus twenty degrees in the belly of the concrete mountain, which turned into an ice-pit in the winter of 1995. Tokody et al developed a three-dimensional computer-processing program, which at the time was considered a novelty. They wrote a separate auxiliary program and built a geographic information system database that assigned to every single beam, the text based data describing their condition and metric parameters.
Remedying the structural problems that had been mapped by the survey was not an easy canter either. From several experts experienced in framework reconstruction, in the end, on the recommendation of the excellent engineers of ÉMI, Dr Béla Kovács and Tibor Andorka, the net-liked cracked external crust was covered by a thin layer of sprayed mortar; the supporting beams were covered with a special plastic-concrete mix, which stopped or even reversed the corrosion processes. As soon as the structural problems of the artificial rock were eliminated, the leaking of the shell improved. There was only one more (however not any less serious) engineering problem to be faced in order to utilise the internal space. This was the horrific level of fluctuations in temperature. The wire lattice structure had no insulation of any kind, which resulted in the usability of the internal spaces being somewhat seasonal!
The architects in their first architectural concept outlined the creation of a “night garden” inside the rock. This concept in reality – by keeping the existing structural elements – would have meant the construction of a heat insulated glass cube structure, separated from the structural elements of the rock and leaving it untouched. The glass structure itself, in the transparent large space separated in this way would have allowed visitors full view of the wonders of the original framework. Yet, it was undertaking even more: looking at the world outside of the cubes as quasi-furnishable glass cabinets, it formed lit, but for visitors inaccessible exhibition spaces from the areas between the glass and the rock crust. If realised, visitors would have undoubtedly become confused sooner or later from this poetically transparent space game, not knowing, whether they were the audience, or at times the watched. In such a space, the roles of the “exhibited” and the “recipient” are sometimes interchanged with everything becoming somewhat relative. In the end, it could have not been realised and the reasons for this are rather ordinary: it is impossible to keep this amount of glass surface clean, especially as the majority of the visitors are fascinated little children. The concept had to be rejected.
The Magical Mountain
The modified concept vision is a cave, carved into the rock block. The new mass forms a crystal-like structure inside the rock that extends into the existing reinforced concrete structure. The shell of the broken form is self-supporting, the new structure following the historically protected reinforced framework of the Great Rock.
The two bodies according to the concept complement one another, making up for an existing shortfall inside the rock. The resolution of this lacking goes beyond the archetypal connection of the rock and the cave (namely, one is positioned inside the other). A kind of dramaturgy has an important role to play, which builds on wandering and observation within the space. The visitor can continuously walk in and out of the new crystal structure, providing the option to admire alternatively one or the other structure from external or internal viewpoints. This experience is reinforced by the observation openings positioned at distinct points.
The internal halls of the rock were fully completed according to the final plans by 2011. The reconstruction added 3,000 m2 of flexible internal space to the 1909 concept (which only intended to utilise a section of the rock), and in addition, the use of renewable energy became one of the guiding threads. The heat from the thermal water feeding the Széchenyi Bath next to the Zoo has also been utilised, with the inclusion of a heat exchange system to supply renewable energy to the Great Rock, amongst the 30 buildings of the Zoo. With this, the operation itself was placed on a more sustainable basis.
The Zoo, which continuously has struggled with a lack of space, gained several thousands of square meters of exhibition area, as well as the option for housing cultural and other events. The wonders of the main structural elements supporting the Great Rock are sensitively highlighted by the reconstruction, and in the coordinated spaces an origami-like layer is added to the organically creasing boundary walls. The deep foundation of the framework, built in the past on a once boggy soil, even made it possible to excavate a complete new level above the base structure, thus they were able to increase the already considerable - so far unutilised - internal volume. Wherever possible, the light enters naturally into the spaces from above. An exciting, playful, accessible, and versatile string of space has been created, providing the Zoo with new opportunities for cultural events.
The Magical Mountain exhibition (Life museum), designed for the internal space of the Great Rock, has set as the objectives - a unique and spectacular presentation of the special life forms that have appeared on the stage of life that is Earth, of the development of life and its impressive richness, where the audience may meet “wondrous rarities”. The principal thread is provided by the multiplicity of life forms and of living and non-living systems, where diversity is interpreted as a response to the challenges of the environment as well as to the problems to be solved; its unique true-to-life appearance is achieved through a range of extremely varied exhibition-technology devices that take advantage of the space.
We have designed an interactive exhibition system with adventurous games, displays of live animals and models of giant animals, with projector microscopes allowing an insight into the micro world. This together with richly equipped discovery areas and lecture theatres creates an exhibition system that can be found nowhere else in Central-Europe.
The Magical Mountain exhibition is divided into a total of sixteen exhibition areas set over four levels; its thematic is divided according to the following areas: Reception hall, Ancient Sea, Time Tunnel, Path of the Ancients, Neanderthal Valley, Life School, Time Machine, Bear Corner, Dark Labyrinth, Colony Gallery, World of the Minute, Hall of Giants, Star Space, Darwin Laboratory, Dino Terraces, Mars Space Station.
Bibliography used in the text:
Kis Péter – Szabon Márta – Persányi Miklós: Nagyszikla (2009)
Dr. Lendl Adolf: Milyen lesz az új állatkertünk? – Fővárosi Közlöny (1909. 6. szám)
Andorka Tibor (ÉMI-TÜV Bayern Kft): szakértői vélemény az Állatkerti Nagyszikla felújítási munkálatairól (2006)
A Budapest Székesfővárosi Állatkert – Magyar Építőművészet (1912. évi 11-12. szám)
Dr. Tokody András: A budapesti Állat - és Növénykert Nagysziklájának geodéziai felmérése (1996)
Andorka Tibor: A budapesti Állatkert vasbeton szerkezetű mesterséges sziklái - Magyar Építőipar (1996. évi 5-6 szám)