Nearly 130,000 pages of declassified Air Force files on UFO investigations and sightings are now available in one place online. Declassified government records about UFOs have long existed on microfilm in the National Archives in Washington, DC. Many of them also live on websites devoted to the topic. But UFO enthusiast John Greenewald says his database, Project Blue Book Collection, is the first to compile every single declassified document from the Blue Book project -- headquartered at Wright-Patterson Air Force Base in Ohio from 1947 to 1969 -- in one place for anyone to search or download for free. The collection consists of files from Project Blue Book, Project Sign and Project Grudge, the names given to official investigations into unidentified flying objects by the United States military. Greenewald's ... says he's just driven by curiosity. "I'm a history buff. I think this stuff should be accessible," he said. "It defied explanation," he said, "and 5,000 FOIAs later my curiosity hasn't gone away." The collection contains 10,000 PDFs, each representing a different case. The files include the details of some of the most famous UFO cases, including the Exeter incident, the Kenneth Arnold sighting and the Mantell crash. Still, Greenewald believes the contents are "just the tip of the iceberg." "It's all a puzzle," he said. "Just when you think you've got all the pieces to make a picture, you realize it's only a piece of a bigger puzzle."