The 500-metre-long Fiat factory at Lingotto, built in 1923 and closed in 1982, is one of the great icons of industrial architecture. After Fiat moved production out, Renzo Piano was asked to repurpose the building: it now houses two hotels, a shopping mall, the Turin Polytechnic, a concert hall, the Pinacoteca Agnelli, and — still — the rooftop test track.
The track is open to the public. Walk a lap of the banked oval, look across the rooftops of southern Turin to the Alps, and look down through the glass "bubble" that Piano slung over the centre of the building. The Pinacoteca Agnelli at one end of the roof holds the personal collection of the Fiat dynasty: small, dense, with Matisse, Picasso, Canaletto and Tiepolo all represented.