Common nickname for a particular maximum-security USAF research facility in southern Nevada, situated within a large training range northwest of Las Vegas. While there is plenty of now-declassified documentation of the base historically being used for the development of high-tech military aircraft (in particular, Cold War reconnaissance planes such as the U-2 Dragon Lady and the SR-71 Blackbird), the facility's current purpose at any one time has always been a closely-guarded secret, which ironically makes it a very famous aspect of various conspiracy theories and general folklore around alien visitors to Earth.
In June 2019, a joke event known as "Storm Area 51, They Can't Stop All Of Us " ostensibly scheduled a raid of the facility for September of that year, notoriously encouraging people to try and dodge bullets by using the Naruto Run. It became such a viral phenomenon that local law enforcement had to explicitly warn people to stay away for their own safety.
