The US government calls Area 51 the Nevada Test and Training Range (Picture: US Department of Defense).
The United States Air Force has warned it "stands ready" to deal with anyone who is to raid Area 51 in the hope of seeing evidence of aliens.
It comes after more than 1.5 million people said they were going to an event on Facebook called 'Storm Area 51, They Can't Stop All of Us'.
The event said: "We can move faster than their bullets. Lets see them aliens."
The event's creator has since admitted the event is a joke.
However, USAF has made it clear it is no laughing matter.
A spokeswoman told The Washington Post: "Area 51 is an open training range for the US air force, and we would discourage anyone from trying to come into the area where we train American armed forces.
"The US air force always stands ready to protect America and its assets."
Area 51, referred to by the US government as Nevada Test and Training Range, is a top-secret military facility as part of the Edwards Air Force Base.