A dossier containing some 3,000 pages of documents relating UFOs that the US government has collected over the past half-century have now been published.
Among the many fascinating accounts of unexplained sightings is the record of a 1952 meeting convened for Pentagon leaders to discuss the CIA's plans to launch a research project on flying saucers.
The minutes of the meeting are just one of the fascinating documents collected in The Black Vault. It’s notable that 1952 is the year of the celebrated "UFO Flap" when a huge number of unexplained objects was sighted in the skies above the US capital.
Later, the CIA moved to give control of UFO research to its Physics & Electronics Division to "take a stand and formulate an opinion as might be required".
This project, known to history as Project Blue Book, had two main objectives: To determine if these "flying saucers" represented a threat to US national security, and to determine what, if any, scientific advantage America could gain over its Cold War rivals by analysing the technology used in these "craft".
The secret meeting appears to have been chaired by A. H. Sullivan, Jr, author of an internal memorandum on "Possible Soviet Flying Saucers".
"Mr Sullivan opened the meeting by saying that a project is to be started in the P&E Division on 'Flying Saucers,'" the document says.
"It was suggested by Dr Odarenko that this project be set up to maintain the file to establish outside contacts on such matters and to build up to date knowledge…to permit the Division and office to take a stand and formulate an opinion as might be required."
Later, a decision is made that "all members of the P&E Division are to look into this project and see what they can contribute to this problem".
Project Blue Book was officially terminated in 1969. It was scrapped after the publication of the Condon Report, which concluded that if UFOs existed at all they were a natural phenomenon.
But in truth, the investigation never ended.
A secret organisation within the Pentagon is still investigating encounters between US military pilots and unidentified flying objects to this day – eight years after its $22 million (£16m) funding lapsed and it was thought to be disbanded.
In 2017, The New York Times reported for the first time that a US military UFO investigation unit called the Advanced Aerospace Threat Identification Program had been in operation between 2007 and 2012, but at the time it was believed to have been shut down.
However, the effort to explain strange phenomena observed by trained Navy and Air Force pilots - such as the unexplained encounter filmed by pilots based on the USS Nimitz - is likely to continue until the aliens, or time travellers, or visitors from another dimension, choose to reveal themselves fully.