SS Thistlegorm, Egypt

When a German bomb tore through her port side in 1941, the SS Thistlegorm sank to a watery grave in the Egyptian Red Sea—and into the annals of diving history. Discovered by nautical legend Jacques Cousteau in 1956, the Thistlegorm is a spectacular sunken museum of motorbikes, cargo trucks, tanks, artillery shells and other World War II relics. Few wrecks can match her for physical grandeur, or for tourist traffic. The Thistlegorm is such a busy dive that, in 2007, Egyptian officials were forced to restrict access as they worked to repair damage done by reckless divers. Still, she stands hull and mast above most of the world's wrecks.