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How aesthetics kill sustainable cities | A review

Master plan of Expo 2000 in Hannover

Forward backThe architectural concept of EXPO 2000 (english version)

To this day, urban planning is often understood only as an aesthetic intervention. But aesthetics often can kill a sustainable and reasonable cities structure. This article appeared more than twenty years ago in Telepolis – Magazine of Net Culture.

At that time I was concerned with the sustainability of the urban development of the Expo 2000 in Hannover. Today this topic is more current than ever. Therefore here is an english version of the original german article.

This article mentions important design concepts of the early 20th century, for example the sun-facing cities by Alexander Klein, Leberecht Migge and El Lissitzky. An integral design approach should use green ventilation corridors and reasonable building orientation and volumes for an optimal cities climate. But integral design concepts are still rare in city planning.

Forward back by Wolfgang Höhl . 17 March 1998
in: Telepolis – Magazin der Netzkultur

The architectural concept of EXPO 2000

In a few years Hannover will host a world exhibition. On the part of the company preparing and constructing the EXPO 2000, this world exhibition is seen as a “… Signal at the beginning of the third millennium …”, an opportunity for ecologically exemplary project preparation and execution. The theme “Man – Nature – Technology” will provide orientation for this world exhibition. The “sustainable development” (Sustainable Development/Agenda 21), the conservation and recycling of resources are the focus of the EXPO planning.

Hanover has an existing exhibition centre (approx. 100 ha) with possible extension areas (approx. 70 ha). This locational advantage, the use of existing areas, helped the City of Hannover to win the contract to hold the World Expo.

The site

Due to the traffic development, the different buildings and the remaining green areas, the Expo area is divided into several separate areas.

The so-called “Messeschnellweg” cuts through the area in a north-south direction. To the west of the Messeschnellweg, the existing exhibition grounds lie like an irregular square. The longest side of the quadrangle lies directly on the Messeschnellweg. This quadrilateral is almost closed in the north, east and west by pavilion buildings, in the middle of this U there is a comb-shaped line in north-south direction, with two flanking, so-called “green fingers”. The existing halls of the exhibition grounds will be made available to exhibitors who do not wish to invest in the construction of their own pavilion.

Along the western border there is another “green finger” that separates the buildings on the West Pavilion from the existing exhibition grounds. Temporary buildings will be erected here, which will be demolished after the Expo. The subsequent use of this area corresponds to the current use as a car park for the trade fair. Further car parking spaces and Karlsruher Straße limit the Expo grounds to the west.

To the south is the main pedestrian access from Laatzen station in the west, across the Allee der Vereinigten Bäume, the pedestrian bridge Mitte, across the Messeschnellweg, to Expo Plaza and across the pedestrian bridge Ost to the tram stop on tram line D in the east. The theme park, consisting of four hall buildings, is located south of the main development in a west-east direction. Kronsbergstraße closes off the exhibition grounds to the south.

The eastern part of the world exhibition grounds is divided into three functional units: the EXPO Plaza, the pavilions of non-governmental organizations such as the EU or the UN, and the pavilions of the host and the nations. All these buildings will be erected permanently and will be reused. The concept for the reuse of the EXPO-Plaza with the adjacent buildings already exists. Thereafter, the arena with 18,000 seats, the planned multiplex cinema and a musical theatre will continue to be used in their original purpose, the World Trade Center Hannover will function as a hotel and office building before, during and after the World Expo, and the German Pavilion can be imagined as an “Academy of the Future”. The use of one of the buildings as a design centre is also under discussion. For the rest of the national pavilion grounds, the responsible persons have already commissioned the development of concepts for subsequent use. Use as a business park is under discussion. The Neue Laatzener Strasse borders the world exhibition grounds in the east.

Several sustainable urban development measures are accompanying the preparations for the Expo within the urban area of Hanover. These include, among others, the redesign of Ernst-August-Platz, Paserelle, Platz am Kröpcke, the construction of the Expo-Café, a reorganisation of the Klagesmarkt, the new construction of the S-Bahn station Hannover Nordstadt and the conversion of the zoo. To the east of the World Expo site, a new residential area is being built, the Hannover-Kronsberg district.


Public transport access to the EXPO site is of particular importance, also at municipal level. In addition to the existing development, the new light rail line D, the new ICE railway station Laatzen in the southwest of the site and an S-Bahn connection between the airport and the EXPO site will be built.

The halls

As a pilot project, Hall 26, erected by Thomas Herzog + Partner, set the standard for all other halls still to be erected. With careful use of materials, the air-conditioning costs for this hall were reduced by 50% and the use of daylight optimised. The shape of the building promotes natural ventilation and allows the diffuse northern lights to be used.

The complex relationships between the building configuration and the thematic behaviour of buildings have been known for a long time. Over a long period of time, many methods for passive climate control were developed by searching for suitable, adapted building forms.

Several criteria are decisive for the favourable thermal behaviour of buildings: the location of the building, its location in relation to topography, vegetation or surrounding buildings, its altitude, the shape and orientation of the building, its volume in relation to its surface, the type of building envelope (proportion of windows) and the type and thermal behaviour of the construction.

Depending on the location and the surface condition, its volume and the respective requirements for temperature control and lighting, the building structure finds its optimal form in the interplay of the temporary turn and the aversion to the respective energy flows of the sun and the wind. It is highly unlikely that this will lead to regular building and development forms.

Already in the twenties of our century Alexander Klein experimented with new building forms, which are based on comprehensive tanning and ventilation analyses. Le Corbusier designed the Maisons Alvéoles, multi-storey buildings regularly interrupted by two-storey loggias. Many buildings of the new settlements of the interwar period have open south and closed north fronts. The gardener Leberecht Migge develops his “southeast-oriented, growing garden settlements with greenhouses”. El Lissitzky expands the medium-scale development of one of his residential projects into a sun-drenched, climatically effective space. Reform ideas for housing and urban development, most of which were not pursued further, or even forgotten.

In the search for an energetically sensible building form, we are now able to use computer simulation to depict even complex flow processes and to make the interactions with the built form visible.

Visions of possible future life have often been a central component of many previous world expositions. For example, visitors to the “Futurama” of the 1939 New York World’s Fair were able to experience the car-influenced city of the future in a model landscape. In 1964/65 it was already cities in the Arctic and under water. On the occasion of the Expo 1967 in Montreal, the first urban development measure to be realised with the habitat of Moshe Safdie was a sustainable example of future forms of living. Analogous to the urban utopias of Yona Friedman, Frei Otto, Walter Jonas, Kisho Kurokawa, Paul Maymont, Paolo Soleri and many others, the concept of Expo 1970 in Osaka developed. The theme pavilions “Past”, “Present” and “Future” appear as urban megastructures under the super roof of Kenzo Tange.

Weaknesses of the urban planning concept

The theme park of Expo 2000 in Hanover is located between the main East and West entrances, spread over four halls. Here, on an area of approx. 100,000 m², various still very unclear visions for life in the 21st century are to be presented. Future and past forms of work are the focus of the “house of unexpected work”. A presentation of the effects of the globalisation of the economy and the “office of the future” can be found in the “factory of existence”. New forms of energy production, the “transparent human being”, health, dangers of epidemics, the future supply of mankind with essential goods and the survival of the world’s population between boundless mobility and the megacities of the 21st century find their place in the halls of the theme park. As one of the main attractions of Expo 2000, a “look into the world of the 21st century” is to be offered here in order to “encourage people to take new paths”. EXPO 2000 in Hanover will have to compete with other major events, such as the Millennium Dome planned in London. If you look at the project status there, the German EXPO with its visions of the future and its architectural concept could easily fall behind.

In contrast to the visions of the theme park in terms of content, the urban layout of the Expo master plan is reminiscent of the large grid-shaped city extensions of the last century, which were supported by housing speculation. The buildings present themselves undifferentiated and uniform according to the points of the compass. Long, uniform axes cut through the complex, leaving one unclear whether they were drawn for future users or just for the pleasure of the architects and builders. The design of the green spaces is reminiscent of the question: “What to do with any remaining space? It seems as if one understands the green as a decorative element that can be used arbitrarily, but hardly climatically effectively. Like an outboard motor, the green space remains a conceptually separate and therefore only a decorative component of the planning. If we want to stick to the ship’s parable, a meaningful, integrative planning shows itself in the equal joining of all design elements to a functional sailing ship.

At these points a conceptual weakness of the urban planning concept becomes apparent. The complex is reminiscent of the traditional formal language of 18th-century urban development, in axes and squares, a reduced, almost purposeless urban development for a bygone social order, reduced to representative functions. An urban configuration that has little in common with the future requirements of a new residential area and a business park of a state capital, the planned subsequent use of the Expo.

For the construction of the pavilions, specifications were developed in which, with the greatest meticulousness, possibilities for energy saving, data on energy consumption and air-conditioning, on water supply and waste water disposal, on the possible recycling of building materials and on the overall energy concept in terms of design and equipment are shown. In the formal urban planning concept (building depth, orientation, development and green planning), on the other hand, one finds an aesthetic measure rather than an intelligent ecological concept.

With intelligent solutions, it is not only the specialist engineer, who is consulted relatively late in the planning process, who is in demand. Intelligent solutions are created in an early joint conception of all parties involved in the planning process. Unfortunately, such solutions are still rare in today’s urban planning. (Wolfgang Höhl)

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