What is Area 51?
You probably know that it's something-something-aliens, but do you actually know what Area 51 is? Well, according to decades of conspiracy theories, it is the top-secret military facility in the middle of the southern Nevada desert where they test on aliens. In reality, it is a 5,000-square-mile, highly classified testing facility of the United States Air Force, administered by the Edwards Air Force Base in Southern California, where top-secret military aircraft is tested. (It is so secret, in fact, that the government didn't officially acknowledge its existence until 2013.) Along with the former Nevada Test Site, it is now part of the Nevada National Security Site.
The area is restricted to both land and area use, and the restricted airspace above the base covers 575 square miles. That's the gist, but because the desert tends to be fertile ground for alien conspiracies (see also: Roswell), the unidentified flying objects allegedly spotted in Area 51's airspace were assumed to be extraterrestrial UFOs, and not the more obvious but far less exciting advanced military aircraft prototypes that they actually were. Locals leaned into it, however, and a whole quirky boutique tourism industry has sprung up around the base.