“One needs to think,
study, develop, invent,
and venture more …”

Frei Otto


It was as if a UFO had landed right in the middle of the city.
The weekly newspaper DIE ZEIT called it “The Wonder of Mannheim” in 1975, when the Multihalle was being built for the National Garden Show and opening up a new architectural dimension.

Carlfried Mutschler and Frei Otto’s filigree curved building is still the world’s largest self-supporting timber grid shell construction. The Multihalle is an icon of architecture and expression of a time defined by the search for new and freer forms of constructing buildings.

Once it was clear that Mannheim would host its first National Garden Show, invitations to tender for planning were announced in two nationwide competitions. Mannheim architect Carlfried Mutschler and garden architect Heinz H. Eckebrecht were subsequently commissioned with the overall planning of the section relating to Herzogenriedpark. For the area that is today’s Multihalle, Mutschler envisaged a temporary construction made of disc-like elements attached to oversized balloons that would provide a canopied space free of supporting columns. When he had to discard the idea of the floating roof landscape due to building regulation concerns, he called on Frei Otto for support. This was not an unusual move, as Otto, who had caused a sensation with the roof design of the Olympic site in Munich in 1972, was known as a progressive thinker whose buildings were frequently created in cooperation with others.

Some passages in this text are taken from the book “Multihalle – Frei Otto, Carlfried Mutschler” by Prof. Dr. Georg Vrachliotis.
More information about the book “Frei Otto. Thinking by Modeling” by Prof. Georg Vrachliotis can be found here.

“Frei Otto saw in his models cultural indicators whose meaning often goes beyond the purely physical haptics of the individual object and that must be understood as experimental symbols for an open society. The Multihalle embodies this like no other 20th century building.”

Prof. Dr. Georg Vrachliotis


Frei Otto designed a roof construction for the Multihalle that was unique at the time. It comprises a filigree lattice structure that spans various spaces: a self-contained function room (the actual hall), walkways, open spaces, and various operating facilities. This timber grid shell roof – still the largest of its kind in the world – contains no right angles and moulds into the park landscape in a biomorphic way.

To visualise the basic idea of a grid shell covered with translucent fabric, Frei Otto and Carlfried Mutschler, in a first joint workshop, made a small concept model out of a finely woven fly screen, using multi-coloured pins to fix it flexibly to a balsa wood base plate.

Mutschler’s concept was to merge the Multihalle visually with the topography of the man-made mounds and artificial watercourses.

The Multihalle consists of two shells that are connected via a canopied walkway. The entire structure measures 160 x 115 metres; the highest dome point is 20 m above the ground. Its widest span is 60 m, its longest is 85 m. The shell construction consists of two resp. four layers of interlaced slats of Canadian hemlock wood, placed 50 cm apart. Each lattice slat is 5.5 cm wide. The shape was calculated at the Atelier Warmbronn with the aid of a hanging model, and photogrammetically assessed and converted into a digital model by Klaus Linkwitz. Ted Happold conducted the complex calculations at Ove Arup’s studio in London.

These construction stability calculations were verified by hanging water-filled waste bins from the roof construction. Assembly work on the monumental wooden grid shell began in 1974. After successful static load tests, the Multihalle was opened on schedule for the National Garden Show in 1975.

In 1981, the awning had to be replaced as the original material, made of PVC-coated blackened trevira fabric, had begun to show leaks. The new, white awning has proved to be significantly more durable.

Today still, the Multihalle is the world’s largest self-supporting timber grid shell structure and considered a predecessor of many contemporary glass dome structures.

In 1978, the Multihalle was awarded the Hugo Häring Prize, the most important architecture prize in the state of Baden-Württemberg. It was granted listed building status in 1998, making it one of Germany’s youngest listed buildings.

The Multihalle’s unique structure continues to inspire architects, urban planners and scientists all over the world, and also the citizens of Mannheim, who are in the midst of rediscovering it as an open and versatile space.


The architect and architectural theorist Frei Otto (* 31. May 1925; † 09. March 2015) was a pioneer of ecological construction and an ‘ambassador’ of organic architecture. His innovative models were inspired by spider webs, leaf structures and soap bubbles. Otto became internationally famous for his organic structural designs, such as the roof of the Olympic site in Munich, which he realised for the 1972 Olympics in cooperation with the agency Günther Behnisch and Partners. Otto’s architectural ideal was building with a minimum amount of material, space and energy, and his models and buildings can be understood as experimental symbols for an open society. In 2015, Frei Otto was posthumously awarded the Pritzker Architecture Prize, which has been granted to outstanding international architects since 1979.

The architect Carlfried Mutschler (* 18. February 1926; † 22. February 1999) has had a decisive influence on Mannheim’s architecture. He designed the extension of the Reiss-Engelhorn Museum, Mannheim’s Stadthaus, the Centre for European Economic Research, the Herzogenried residential estate, and numerous schools and churches across the city. Mutschler’s early work was clearly influenced by his studies under Egon Eiermann in Karlsruhe, and it is distinctive and characteristic in its clear lines, edges, and exposed concrete. In the 1950s, however, an encounter with Hans Scharoun’s and Hugo Häring’s expressionist buildings led to a change in his style. Despite his teaching activities in Stuttgart and Frankfurt, Mutschler’s life centred around Mannheim, where he was born and grew up.


Besides its pioneering technical engineering position in architectural history, the Multihalle still has major implications for Mannheim’s urban development. The focus of the German National Garden Show (Bundesgartenschau) of 1975 marked a characteristic point in Mannheim’s evolution from an industrial city into an innovative, modern city, symbolically epitomised by the landmark structure in Herzogenriedpark.

The redesign of Herzogenriedpark and the Herzogenried housing development as a new model of ‘living in the green belt’ represented urban development measures that improved the district above and beyond the purpose of the National Garden Show. The city and the local borough also benefitted from the Multihalle as a versatile venue for clubs, associations and other institutions for many years.

The preservation of the Multihalle is a commitment to the city as a whole, just as its construction was a commitment to that particular district of Mannheim. It opens opportunities for connecting the Mannheim districts and their various leisure, cultural and educational facilities across the Neckar river – though located on the outskirts of the centre, it provides a central meeting place that can give rise to new developments, be positively perceived and make a positive impact far beyond the city limits.