Its existence has been a badly kept secret for decades and it has fuelled the imaginations of conspiracy theorists and UFO hunters around the world.
Now the existence of Area 51 has been officially acknowledged by the Central Intelligence Agency and its exact location revealed in Nevada.
Documents released by the CIA also reveal that there really have been some strange occurrences at the secret airbase – however, they are not quite as exciting as UFO hunters would like.
Among the jobs that staff at the site had to perform during the 1960s was a routine of vacuuming the runway to allow experimental aircraft to take off without damaging their engines.
Previously the US government has provided minimal information about Area 51 and most mentions of it are redacted in documents that are declassified.
Official maps usually only show a disused mine at the site or a large area of restricted airspace, however it does feature on Google Maps and in satellite images.
However, in a set of documents released to a researcher studying the history of the U-2 spy plane program, the secret base is officially revealed.
A line drawn map contained within the reports show the location of Area 51 and Groom Lake, the salt flat the base is built upon, in relation to the Mojave Desert.
They also provide details on how the site was first established as part of a wider Atomic Energy Commission test site.
However, the documents make no mention of UFOs nor the secret weapons that many believe are being developed there.
Jeffrey Richelson, a senior fellow at the George Washington University’s National Security Archive who obtained the records, said the new documents seemed to suggest the CIA were becoming less secretive about Area 51’s existence.
The documents were released in response to a Freedom of Information Request made in 2005. An earlier 2002 request resulted in documents that were heavily redacted.
In a blog posted on the research organisation’s website, Mr Richelson said: “What the CIA released in response to a 2005 Freedom of Information Act request is a substantially less redacted version of a history of two key aerial reconnaissance programs.