Rooftop Racetrack, Lingotto Automobile Factory, Via Nizza, Turin, Italy

The factory became outmoded in the 1970s and the decision was made to finally close it in 1982. The closure of the plant led to much public debate about its future, and how to recover from industrial decline in general. An architectural competition was held, which was eventually awarded to Renzo Piano, who envisioned an exciting public space for the city. The old factory was rebuilt into a modern complex, with concert halls, theatre, a convention centre, shopping arcades and a hotel. The eastern portion of the building is the headquarter of the Automotive Engineering faculty of the Polytechnic University of Turin. The work was completed in 1989. The track was retained, and can still be visited today on the top floor of the shopping mall and hotel.
The only similar rooftop test track was in Nessonvaux, Trooz, Belgium. From 1928 to 1958, Imperia had a track over 1 km long which was built partially on top of the factory.