The treasure trove is stashed away in a nondescript building in the Stuttgart area. Hundreds of cars (including prototypes, one-offs and race cars) are hidden behind closed doors and occasionally taken out for special events like motor shows and new car launches.

Autocar got a private tour with the lucky man, Alexander Klein, whose job it is to curate - and guard - its priceless cars. Here’s our pick of the best Porsches you’ve (probably) never seen before: