Hanging from the fringes of an industrial estate at Audi’s Ingolstadt headquarters sits an unassuming, corrugated-clad building. There’s no address on the door, no doorbell, and one-way windows.

To get in you must use an American-style phone box. There you’ll speak to a man, who, once vetted, will buzz you in through three borderline-bulletproof doors.

This is Audi’s hush-hush hangar, something the German firm is very keen to keep a secret. It contains Audi’s entire back catalogue, with 600 rare, often priceless cars spread over many floors. Even Top Gear isn’t permitted to see everything, but thanks to a lot of arm-twisting we’ve been granted access to just one floor. Level 2.

Thankfully Level 2 contains the best stuff: motorsport. Some of the most legendary, revolutionary race cars to ever grace the planet, all wonderfully covered in crap from their last race and parked up as if in an NCP.

Silver Arrows, Alpine trials winners, Le Mans legends, rally revolutionaries, Pikes Peak punishers and touring car champs, they’re all here. And all have some pretty juicy stories behind them.

So click forward to discover how Audi has dominated or changed pretty much every single type of motorsport it’s ever entered. Oh, and some very pretty pictures.

Words and Pictures: Rowan Horncastle