In the early morning of July 20, 1952, Capt. S.C. “Casey” Pierman was ready for takeoff at Washington National Airport, when a bright light skimmed the horizon and disappeared. He did not think much of it until he was airborne, bound for Detroit, and an air traffic controller told him two or three unidentified flying objects were spotted on radar traveling at high speed.

The controller told Captain Pierman to follow them, the pilot told government investigators at the time. Captain Pierman agreed, and headed northwest over West Virginia where he saw as many as seven bluish-white lights that looked “like falling stars without tails,” according to a newspaper report.

The sighting of whatever-they-were garnered headlines around the world. And in the decades since, U.F.O.s have become part of the pop culture zeitgeist, from “Close Encounters of the Third Kind” to “The X-Files.” In September, a star of that long-running series, Gillian Anderson, will appear in “UFO,” a movie about a college student haunted by sightings of flying saucers. A “Men in Black” remake is in the works. And the History Channel plans to air “Project Blue Book,” a scripted series about the government program that studied whether U.F.O.s were a national threat.

And the topic is back in the headlines. Last year, The Times wrote about a little known project founded in 2007, the Advanced Aerospace Threat Identification Program, to investigate U.F.O. sightings. A search of The Times’s historical archives reveals a rich bounty of U.F.O. sightings, lore and explanations since the 1950s. And who can forget in 2016 when Hillary Clinton said she would reopen the real X-files if she were president?