The Autòdrom de Sitges-Terramar is one of the world's most evocative abandoned racetracks: an intact 1923 high-banked concrete oval sitting forgotten behind farmland a couple of kilometres west of the town. Built in just 300 days for the 1923 Spanish Grand Prix, it bankrupted its developer, was never officially used again, and has been crumbling quietly for more than a century.
Access has always been semi-clandestine — the site is private property — but the place is a magnet for car enthusiasts, photographers, and urban explorers. Recent restoration plans have circled but stalled. Check locally before walking out; it lies just off the road to Sant Pere de Ribes.