here in the 1950s and will many believers believe they keep captured alien life forms and reverse engineered downed alien craft starting with the rosswell wreckage of the '40s. conspiracy theories fueled by this base worker interviewed back in '89. >> the power source is an anti-matter reactor. >> suspicious sightings ever since. >> you see a lot of things in the sky that you can't really identify. >> the air force claims these 60 square miles are reserved for aircraft testing and that's it. >> this astronomer agreed. >> clearly, there are aliens out there, and i think that's a pretty strong argument, but we don't have the proof of that and i don't think it's stocked up in southern nevada. honestly, i don't. roberts' best estimate, 20,000 people will actually show up here. some, hoping to find out if there's really anything in there, all dreaming there really is something out there.