or advanced divers, the thrill of the 158m 'Vandy' starts with a drop down one of the 11 elevator shafts, choosing any floor to enter. Those with less technical training can still freefall into the elevator and cargo shafts of this Air Force missile-tracking ship off the coast of Key West, Florida.

Downed in 2009, this artificial reef has been cleaned of hazards, and made safer with doors removed and blowtorch-added exit points. Unique to the ship are the 2m resident goliath grouper and the ship’s satellite dishes that divers pop out of following swims through the interior. Oh, and the vessel served as a set for the sci-fi flick Virus – hence the Russian lettering in the passageways.