Project Blue Book, the U.S. Air Force investigation into UFOs that lasted from 1952 until 1970, has been readily available for some time, but searching through the hundreds of thousands of documents can be a daunting task. So, The Black Vault has compiled all the cases into an easy-to-search database. The project's founder John Greenewald provided International Business Times with a few of Project Blue Book's most famous and interesting cases.

Mantell UFO Incident

This is one of the most interesting cases from Project Blue Book. On Jan. 7, 1948, Captain Thomas F. Mantell, a Kentucky Air National Guard pilot, chased a UFO first spotted by Kentucky police. An officer sent a report to Godman Army Airfield and officers in the control tower also saw the object. Mantell tracked the object up to 20,000 feet before he blacked out due to lack of oxygen. Mantell's plane spiraled out of control and the pilot was killed in the crash. The Project Blue Book files contain eyewitness accounts and photos of the crash. Project Sign, Blue Book's predecessor, concluded the UFO was actually Venus but the Blue Book determined it was a Skyhook balloon, which was a classified project at the time.

Lonnie Zamora Incident

On April 24, 1964, several individuals reported seeing a UFO over Socorro, New Mexico. Lonnie Zamora, a New Mexico State police officer, witnessed the UFO on the ground before it took off. "He said the object was white, egg or oval-shaped and apparently supported on girderlike legs. He said be heard a roar and saw smoke and flame coming from the bottom of the object," reads Zamora's description of the craft. The UFO reportedly left impressions and burn marks.

Perhaps the best thing about the Zamora incident is the amount of media coverage it received and the commentary by the Project Blue Book author. "I would conclude the following: That Zamora, although not overly bright or articulate is basically sincere, honest, and reliable. He would not be capable of contriving a complex hoax, nor would his temperment indicate that he would have the slightest interest in such," reads one passage.

In another correspondence, astronomer J. Allen Hynek discusses his investigation of the site and the charred area. There was some talk that the burned bush was radioactive and Hynek has some fun with the news, closing out his letter by saying, "The bush drew blood when I attempted to get some soil samples. Undoubtedly, the finger will now wither away from radiation burns. Unfortunately, I do not have interplanetary Blue Cross coverage!"

The investigation went to great lengths to figure out just what happened in New Mexico, including some inquiries to NASA regarding lunar module projects, but the investigation could not determine what happened that day. Photos of the site can be found here.

"You can see this was something taken seriously and it does have an unexplained stamp on it, meaning it was something the military just could not explain," Greenewald said. "If you dismiss all 12,617 other cases and you take this one, this one by itself proves something is going on. You cant just dismiss this case as a hoax. Maybe this police officer really got it in him to scorch some dirt and make up this grandiose story. Or maybe something strange really did happen."

Betty and Barney Hill Abduction

The Betty and Barney Hill abduction is interesting for the reports surrounding the case. The Project Blue Book documents are kind of dull, but the investigation quickly concludes the UFO sighting was likely an advertising search light. Per their interivews, the Hills said they saw a UFO following their car as they were returning home from vacation in September 1961. The abduction was later revealed during a regression therapy session in 1963. Under hypnosis, Barney and Betty discussed their abduction and the scientific experiments performed by their aliens.

So Many UFO Sightings In 1952

Sometimes, it's not about a particular case but the whole trend. In 1952, there were a huge number of reported sightings, which peaked in July with reports of UFOs over the White House. "On 19 and 20 July, radar scopes at Washington National Airport and Andrews Air Force Base tracked mysterious blips. On 27 July, the blips reappeared. The Air Force scrambled interceptor aircraft to investigate, but they found nothing," reads the CIA's description of what happened over consecutive weekends. In 1952, there were more than 90 different reports of UFO sightings over U.S. Air Force bases, more than four times the number of reports from the previous year.