The small US cities of Rachel and Hiko, near the top-secret Area 51 facility in Nevada, are being prepared for possible influx of visitors.
The viral event on Facebook "Storm Area 51
what is Area 51?
What do we know about Area 51?
Area 51 refers to the location of the map and is the popular name for the United States Air Force. It is located at Lake Groom, a dry lake in the Nevada Desert, 85 miles (135 km) north of Las Vegas.
What is happening inside is extremely secretive. Members of the public are protected by warning signs, electronic surveillance and armed guards.
It is also illegal to fly over Area 51, although the site is already visible in satellite images. The base has runways up to 12,000 feet (2.3 miles) long.
The facility is located in two other restricted areas of war: the Nevada Test Area, where US nuclear weapons were tested from the 1950s to the 1990s, and the range for testing and training in Nevada.
The whole range covers over 2.9 million acres of land.
According to the US military, it represents a "flexible, realistic and multidimensional battle space for developing tactics for testing and refining training."
Why was it built?
Area 51 was created during the Cold War between the US and the Soviet Union as an aircraft test and development facility, including the U-2 and SR-71 Blackbird reconnaissance aircraft
Although opened in 1955, its existence officially recognized by the CIA in August 2013.
Four months after the CIA's announcement, President Obama became the first US president to publicly mention Area 51.
What's going on there today?
Although official information is scarce, it is believed that the US military continues to use Area 51 to develop avant-garde aircraft. It is estimated that about 1,500 people work there, many of whom charter flights from Las Vegas.
Ani Jacobsen, who wrote on Area 51 history, told the BBC that some of the most modern espionage programs in the world are in place.
'Area 51 is a testing and training facility. Investigations began with the U-2 spy plane in the 1950s and have now turned to drones, "she says.
Are there alien and flying saucers in Area 51?
The mystery of about 51 helped nourish many conspiracy theories.
The most famous is the claim that the site hosts an alien spacecraft and the bodies of its pilots after they crashed in Roswell, New Mexico, in 1947. The US government says that there were no aliens and the catastrophe the ship was a meteorological balloon.
Others claim to have seen a UFO above or near the site, while some say they were abducted by aliens and even experimented before being returned to Earth.
And in 1989, a man by the name of Robert Lazar claimed to have worked on alien technology in Area 51. He claimed to have seen medical images of aliens and that the government was using the facility to investigate UFOs.
Linking Area 51 to extraterrestrials can serve as a useful distraction for intelligence agencies.
"Back in 1950, the CIA set up a UFO office to monitor unidentified flying objects over Nevada. When people first saw the U-2 spy plane, nobody knows what they see,"
"The CIA uses this misinformation to its advantage by promoting alien mythology."
1955 Annual facility open
2013 Year it this existence was officially first recognized
2.3 miles length of longest runway
1,500 Number of people believed to be working at the facility
happens if people "storm" Zone 51  20-year-old Mattie Roberts made a Facebook event suggesting that "we can run faster than their bullets. Let's see them aliens. "Two million people said they were" going ", even though the related festival was moved because of fears of a" possible humanitarian catastrophe. "
Warning signs around area 51 make it clear that intruders will not be tolerated.
USAF warned that Area 51 "is an open range for US Air Force training, and we would discourage anyone trying to enter the area where we train the US Armed Forces."
He added, "The US Air Force is always ready to protect America and its assets."