I was too early: in the mid-nineties I had visited the first Building at the Vitra furniture factory in Weil am Rehin, at the German-Swiss border. Frank Gehry's chair museum was the only building open to the public. Now I was finally back, to hold a public interview with Renny Ramakers of Droog Design, and there was a lot to see. Under the unflagging leadership of Rolf Fehlbaum the Vitra 'campus' has become a lifesize collection of contemporary architecture and modern-day classics. An architectural petting zoo.

Fehlbaum already has a collection of 6.000 chairs and 2.000 lamps, and has been scaling up for several years now to buildings. One of the new additions is a geodesic dome by Buckminster Fuller which he bought at an auction in Detroit, shipped home and restored for use as an exhibition and party venue. On vacation in France he came across Jean Prouvé's 'Relais du Sanglier', a prefab gas station from 1953 that had fallen into disuse. Felhbaum fell in love with it, says our guide, not in the least because the first chair of his huge collection was a Prouvé. And on the grass near the VitraHaus showroom stands a shiny 1968 Airstream mobile home that he found in Nevada and, again, shipped home.

The Portuguese architect Alvaro Siza built his first factory here for Vitra, a chic and restrained building with a bridge that is lowered when sensors detect rain in order to protect the goods moving from one factory building to another, and is raised on dry days so as not to disturb the view of the surroundings.

It was Vitra, if I am not mistaken, that gave Zaha Hadid her first chance to really build. Her fire station was decommissioned after three years (I can hardly believe Vitra ever needed five fully equipped firetrucks all for itself?) but even empty, the building is amazing. Guide Carol: 'We see it as a prototype.'  

The bigest showpiece in the lifesize architecture collection is Herzog de Meurons enormous VitraHaus showroom of 3300 m2, opened in 2010. The architects are known for, among other things, their Allianz stadium in Munich, their makeover of a power station into the Tate Modern, and the Olympic stadium in Beijing. VitraHaus is made of twelve 'typical  Swiss' houses but then stretched and piled up one on top of the other to form a mountain (Alp?). The one on top weighs 1000 tons and cantilever 15 meters out over the rest - quite an engineering feat. The houses have no windows, the only light comes through the glass ends. It could easily have been comic book-like, as is Sjoerd Soeters' hotel in Zaandam, and it is probably about as far as HdeM go with regards to humor, but it is actually quite beautiful. 

There is an even newer member of Vitra's architectural family in the offing: a building by Sanaa. Vitra hopes to have it finished by the end of this year. What's next?