Area 51. It's the most famous military institution in the world that doesn't officially exist. If it did, it would be found about 100 miles outside Las Vegas in Nevada's high desert. Then again, maybe not - the U.S. government refuses to say. You can't drive anywhere close to it, and until recently, the airspace overhead was restricted - all the way to outer space. Any mention of Area 51 gets redacted from official documents, even those that have been declassified for decades. It has become the holy grail for conspiracy theorists, with UFOlogists positing that the Pentagon reverse engineers flying saucers and keeps extraterrestrial beings stored in freezers. Urban legend has it that Area 51 is connected by underground tunnels and trains to other secret facilities around the country. Well, now, for the first time, someone is ready to talk - in fact, five men are, and their stories rival the most outrageous of rumors. Colonel Hugh Slip" Slater, 87, was commander of the Area 51 base in the 1960s. Edward Lovick, 90, ... spent three decades radar testing some of the world's most famous aircraft. Kenneth Collins, 80, a CIA experimental test pilot, was given the silver star. Thornton "T.D." Barnes, 72, was an Area 51 special-projects engineer. And Harry Martin, 77, was one of the men in charge of the base's half-million-gallon monthly supply of spy-plane fuels. As for the underground-tunnel talk ... Barnes worked on a nuclear-rocket program ... in Area 51's backyard. "Three test-cell facilities were connected by railroad, but everything else was underground," he says.