Bletchley Park was where Germany's then-powerful Enigma encryption was cracked by none other than Alan Turing. It was key to the information war the took place behind the scenes in WWII. It was also where the first programmable digital computer, the Colossus 2 was built. The predecessor to this beast, the Colossus, cracked Lorenz, Germany's other encryption scheme. Not surprisingly, the site is now a museum.