PHOENIX -- Hundreds of UFO enthusiasts are gathered at the Fort McDowell Resort for the 24th Annual International UFO Congress.
Speakers are addressing a variety of subjects, including aliens, abductions and unidentified flying objects (UFOs).
According to the National UFO Reporting Center, Arizona ranks seventh among states for the most UFO reports, more than 3,100 posted on its website in the past 15 years.
Last month nearly 130,000 pages of declassified United States Air Force files on UFO sightings and investigations were compiled on theblackvault.com. The site's founder, John Greenwald, spent years filing Freedom of Information Act requests for the government's files on UFOs. They had existed on microfilm in the National Archives in Washington, DC but Greenwald said his free site offered the only single source for them - that was until recently when, according to his site, he was forced to remove the online files due to digital copyright claims by a company.
The files came from Project Blue Book which was based at Wright-Patterson Air Force Base in Ohio. The Air Force recorded more than 12,000 sightings between 1947 and 1969. According to an Air Force fact sheet, they stopped investigating after concluding "no UFO reported, investigated and evaluated by the Air Force has ever given any indication of threat to our national security" and "there has been no evidence indicating that sightings categorized as 'unidentified' are 'extraterrestrial vehicles.' "