Ah, Area 51. The beginning and the end of most conspiracy theorists' quests for an alien scandal. A place so famous, and yet so secretive, that you could make up any old nonsense and plausibly say that it happened there. And yet here it is on our list, still a possible contender as a suspected alien hideout. Because even if you strip away the nonsense, it's still a very dodgy place.
Groom Lake, Homey Airport, Dreamland, Paradise Ranch, R-4808N. The place has so many classified and declassified names, even its current status is hard to keep track of. All we really know for sure is that it exists in Lincoln County, Nevada, as a top-secret installation attached to the Edwards Air Force Base. In fact, it wasn't until 2013 that the CIA actually even acknowledged that the base existed.