Over 600,000 people have signed up to an event to “storm Area 51” – the top secret US military base in the Nevada desert – in a quest to “see them aliens”.The event, titled “Storm Area 51, they can’t stop all of us”, invites attendees to congregate en mass before entering the base together.The event, organised on Facebook, appears to be a tongue in cheek invitation, rather than the first signs of a radical civil disobedience movement.This is made clear by the reference to the highly-classified military base as the “Area 51 Alien Centre tourist attraction”.“If we naruto run, we can move faster than their bullets. Lets see them aliens,” the invitation says.To “naruto run” is to run at high speed in the style of Naruto Ozumaki – title character in the Japanese anime series Naruto – who runs with his head down and arms behind his back. The event, if it can be called such, is scheduled for 20 September.The mysterious and heavily guarded Area 51 has been at the centre of numerous conspiracy theories for decades, with supposed connections to humanoid alien life forms and their supposed space ships.It featured in the 1996 alien invasion film Independence Day as an alien testing laboratory, but the base’s real primary function remains unknown.It was only formally recognised as a military base in 2013 following a 2005 Freedom of Information Act request.The perimeter of the base is constantly patrolled by armed security guards and CCTV and motion-sensor cameras are also in use.Signs around the base advise that “deadly force” is authorised against trespassers.Military aviation website TheAviationist.com spoke to a local company which offers tours up to the edge of the Area 51 facility, and who warned any attempt to reach the base would be “very stupid”.Donna Tryon reportedly said: “Area 51 is not a joke. No matter what is going on there, people need to remember, this is a military facility. You wouldn’t get far.”The website detailed an incident in which a tour driver from the company had inadvertently crossed into the restricted area which resulted in the arrest of the driver and the vehicle’s occupants. On previous occasions the tours have been “buzzed” by military aircraft, and people have had red laser sight dots appear on their foreheads from the desert, the website said.Though the invitation to storm Area 51 appears to be a joke, last month The Pentagon provided a very real classified briefing to members of Congress about reported encounters by US navy pilots with unidentified aircraft, some of which were said to have no visible engines and could reach hypersonic speeds.Earlier this year, a number of pilots reported seeing the objects on an almost daily basis from the summer of 2014 to March 2015 while flying navy jets off the East Coast. Some of the encounters were captured on video and lead the navy to announce it had updated the way pilots were to formally reports the incidents.“Navy officials did indeed meet with interested congressional members and staffers on Wednesday to provide a classified brief on efforts to understand and identify these threats to the safety and security of our aviators,” the navy said in a statement last month.“These things would be out there all day,” Lt Ryan Graves, an F/A-18 Super Hornet pilot with ten years experience with the navy, told the New York Times in May. “Keeping an aircraft in the air requires a significant amount of energy. With the speeds we observed, 12 hours in the air is 11 hours longer than we’d expect.”