Project Blue Book was the longest running of the U.S. government’s official inquiries into UFO sightings, compiling reports on more than 12,000 sightings or related events from 1952 to its dismantling in 1969.

A WWII veteran fighter pilot was just finishing a cross-country flight when a strange white light appeared on his wing. After it made aggressive moves, he engaged with it in the night sky for 27 minutes—but it outmaneuvered his plane, sometimes at speeds exceeding 400 m.p.h. The government called it a weather balloon. Read more

It was dusk when the Mays boys and their friend Tommy saw a pulsing red light streak from the sky and crash on a nearby farm. With their mom and some older boys, they high-tailed it up the hill to get a better look—and came running back down in terror. Through a dense mist, they say, they saw a 10-foot-high monster with a glowing green face. Read more

Over a two-week stretch, hundreds of residents in this university town—including several prominent scientists—saw mysterious blue-green lights streaking across the night sky. One Texas Tech freshman snapped pictures, which show a cluster of lights in a “V” formation. The official explanation: migratory birds reflecting street lights. Read more

Two Eastern Air Lines pilots reported seeing a cigar-shaped aircraft with two rows of windows. But after investigators generated a top-secret report, the Air Force incinerated it. Some wonder if the craft was Soviet, or part of the rocketry tests being run by former Nazi aerospace engineers spirited to the U.S. after the war. Read more

Witnesses reported seeing “green balls of fire” in the skies around the Los Alamos and Sandia atomic-weapons laboratories and other highly sensitive military installations. In one instance, the fireball raced head-on toward a plane, forcing the pilot to swerve. Some explanations: Soviet spy devices, nuclear fallout debris or an alternate form of lightning. Read more

Scoutmaster Sonny DesVergers was driving some Boy Scouts near West Palm Beach when they saw a bright light flash over a palmetto grove. He stopped to investigate—and later emerged terrified, with burns on his arms and a tale of a 30-foot diameter saucer that had enveloped him in a red mist. Grass in the grove was singed, and its roots charred. Read more

Betty and Barney Hill couldn’t understand why the light was chasing their car. But after some rhythmic beeping, they got drowsy and woke up two hours later, 35 miles away, disheveled and confused. Years later, hypnosis helped them recover memories of an abduction by gray humanoid creatures who led them into a saucer and conducted invasive tests. Read more