(ABC News) -- Area 51 in Nevada has long been the subject of wild conspiracy theories about extraterrestrials, time travel and alien autopsies, but newly released declassified documents from the CIA finally acknowledge its existence.
Although the report makes no mention of the sensational stories that have played out in pop culture for decades, it turns out that Area 51 was started as a testing site for the government's U-2 spy plane. The report, more than 400 pages, is titled "Central Intelligence Agency and Overhead Reconnaissance: The U-2 and Oxcart Programs, 1954-1974."
The U-2 spy planes were commonly used by the United States during the Cold War in reconnaissance missions around the globe.
Officials and former employees have previously acknowledged in passing the existence of the facility and how it was used for testing U-2 planes, but this is the first time the U.S. government has openly referred to Area 51 and given specifics on its operations. The report also features a map of the area.
It makes no reference to the status of Area 51 after 1974.
The U-2 planes flew at an altitude of 60,000 feet, which was higher than any other plane at the time, according to the documents. When people who lived nearby saw the unfamiliar planes, they became suspicious and believed Earth was being visited by aliens.
"High-altitude testing of the U-2 soon led to an unexpected side effect -- a tremendous increase in reports of unidentified flying objects (UFOs)," the report states.
Air Force investigators then attempted to explain such sightings by linking them to natural phenomena, the report says.
"U-2 and later OXCART flights accounted for more than one-half of all UFO reports during the late 1950s and most of the 1960s," according to the documents.
Security at the facility and its secretive nature have been a constant in the years since Area 51 officially opened for business in 1955.
"As the deliveries of U-2 airframes to the testing site increased, a major logistic problem arose: how to transfer Lockheed employees from Burbank to Area 51 without arousing a great deal of curiosity," according to the documents.
"The project staff decided that the simplest approach would be to fly the essential personnel to the site on Monday morning and return them to Burbank on Friday evening."
The information also documents three fatal crashes that took place during 1956 with U-2 planes.
To make Area 51, a facility "in the middle of nowhere," sound more attractive to workers, it was referred to as "Paradise Ranch," or simply "the Ranch."
George Washington University's National Security Archive obtained a CIA history of the U-2 spy plane program through a Freedom of Information request and released it Thursday.
National Security Archive senior fellow Jeffrey Richelson reviewed the history in 2002, but all mentions of Area 51 had been redacted, according to The Associated Press.
Richelson says he requested the history again in 2005 and received a version a few weeks ago with mentions of Area 51 restored.
Will the conspiracy theories finally come to an end? Not likely, and after all, some parts of the report are still redacted.