Less than eight feet of the fifty-five-foot-long pole is visible here. The rest of the pole is underground, below a concrete pad, and rises up from an underground chamber built inside the desert floor. (Collection of Roadrunners Internationale/CIA) (Collection of Roadrunners Internationale/CIA)

Working at night meant less of a chance of being surveilled by Soviet spy satellites. "Getting an aircraft up on the radar test pole took eighteen minutes. It took another eighteen minutes to get it back down," says Ed Lovick. "That left only a set amount of time to shoot radar at it and take data recordings." As soon as technicians were done, they took the aircraft down and whisked it away into its hangar. (Collection of Roadrunners Internationale/CIA) (Collection of Roadrunners Internationale/CIA)

Area 51 as seen from the air, circa 1964. This rare photograph has never been published before. (Collection of Roadrunners Internationale) (Collection of Roadrunners Internationale)

Yucca Flat, which spans several Areas at the Nevada Test Site, is one of the most bombed-out places on earth. In this photo taken during the winter months from a helicopter above Area 10, the Sedan Crater can be seen in the forefront. A 104-kiloton bomb was buried at a depth of 635 feet, and its detonation produced a crater 1,280 feet wide and 320 feet deep, moving 12 million tons of radioactive dirt in an instant and creating a hole that can be seen from s.p.a.ce. (National Nuclear Security Administration) (National Nuclear Security Administration)

Ed Lovick, at Skunk Works in the mid-1960s, with the waveguide, as he works to reduce the radar cross section for the A-12 to meet the CIA"s demands. (Collection of Edward Lovick/Lockheed Martin) (Collection of Edward Lovick/Lockheed Martin)

A-12 ejection-seat test on Groom Lake"s dry lake bed. (Collection of Roadrunners Internationale/CIA) (Collection of Roadrunners Internationale/CIA)

The A-12 Oxcart hidden behind a barrier at Area 51. It took 2,400 Lockheed Skunk Works machinists and mechanics to get a fleet of fifteen ready for the CIA. Visible on either side of the aircraft are the uniquely adjustable inlet cones that regulated airflow and allowed the CIA spy plane to cruise in afterburner and reach peak speeds of Mach 3.29 by May 1965. (Lockheed Martin) (Lockheed Martin)

Richard Bissell, known best for his role in the Bay of Pigs fiasco, was the CIA officer who built Area 51 from the ground up. In this rare photograph, he shakes hands with CIA pilot Louis Schalk after the first flight of the A-12 Oxcart in April 1962. Bissell had already resigned. (Lockheed Martin) (Lockheed Martin)

The A-12 Oxcart lands on the runway at Area 51, April 1962. (Collection of Roadrunners Internationale/CIA)

Charlie Trapp was chief of Rescue and Survival at Area 51 from 1962 to 1967. It was in this H-43B helicopter that Trapp found the body of Oxcart pilot Walt Ray and his airplane after a fatal crash. Trapp received the Air Medal for the twenty-five-day operation. (Collection of Charles E. Trapp) (Collection of Charles E. Trapp)

CIA pilot Ken Collins, in full flight gear, hanging above the Area 51 swimming pool during ocean-survival training circa 1965. Charlie Trapp sits on the diving board with a technician, name unknown. (Collection of Charles E. Trapp Jr.) (Collection of Charles E. Trapp Jr.)

Radar station at the top of Bald Mountain. (Collection of Charles E. Trapp Jr.) (Collection of Charles E. Trapp Jr.)

The A-12 trainer during a test flight. Note the two canopies, one for the instructor pilot and another for the trainee. The A-12 trainer aircraft could not reach the upper Mach numbers; CIA pilots experienced that remarkable feat on their own. (CIA) (CIA)

This CIA project, code-named Tagboard, was an Oxcart with a Mach 3 drone on its back, circa 1965. To avoid confusion with the A-12, the mother ship was designated M-21 (as in "mother") and the drone was designated D-21 (as in "daughter"). (Collection of Lockheed Martin) (Collection of Lockheed Martin)

Former U-2 spy plane pilot Tony Bevacqua flies over Hanoi in the fabled SR-71 Blackbird, the Air Force variant of the A-12 Oxcart. This reconnaissance photograph shows an SA-2 missile being fired at Bevacqua from a ground station below. It was the first time an SR-71 was ever fired upon. July 26, 1968. (Collection of Tony Bevacqua/U.S. Air Force) (Collection of Tony Bevacqua/U.S. Air Force)

Colonel Hugh "Slip" Slater served as commander of Area 51 during the Oxcart program. Before he was put in charge of Project Oxcart, he served as commander for the CIA"s Black Cat U-2 Squadron, which flew covert espionage missions over China. Here he is with the YF-12, the attack version of the A-12 Oxcart, circa 1971. (Collection of Colonel Hugh Slater/U.S. Air Force) (Collection of Colonel Hugh Slater/U.S. Air Force)

Area 51 as seen from above in 1968. (U.S. Geological Survey/Federation of American Scientists) (U.S. Geological Survey/Federation of American Scientists)

Frank Murray started out flying chase on Project Oxcart in the F-101 Voodoo. After CIA pilot Walt Ray was killed outside Area 51 during testing, General Ledford asked Murray to take Ray"s place. Here Murray is on Kadena, Okinawa, before a Black Shield mission over North Vietnam. (Collection of Frank Murray) (Collection of Frank Murray)

Jack Weeks and Ken Collins preparing for a Black Shield mission over North Vietnam, inside the command center on Kadena in 1968. A few months later Weeks would be preseumed dead; no trace of the A-12 airplane or his body was ever found. (Collection of Ken Collins) (Collection of Ken Collins)

Area 51 radars, circa 1968. T. D. Barnes and his fellow EG&G Special Project engineers worked in the building at left. To pa.s.s the time when the Soviets pinned them down with spy satellites, they pulled pranks, like painting odd-shaped aircraft on the tarmac and heating the images up with hair dryers to add a heat signature. (Collection of Thornton D. Barnes/Roadrunners Internationale) (Collection of Thornton D. Barnes/Roadrunners Internationale)

Radar antennae on the outskirts of Area 51, 1968. (Collection of Thornton D. Barnes/Roadrunners Internationale) (Collection of Thornton D. Barnes/Roadrunners Internationale)

T. D. Barnes, age nineteen, serving in Korea in 1956. A photo of his new bride, Doris, sits on his desk in this photograph, as it still does in 2011. Barnes, a radar expert, started working for the CIA in 1958. (Collection of Thornton D. Barnes) (Collection of Thornton D. Barnes)

The Beatty High Range, where radar expert T. D. Barnes worked for joint NASA/CIA projects prior to his transfer to Area 51. From Beatty, Barnes could track airplanes over at Groom Lake, sixty miles as the crow flies. (NASA) (NASA)

A Russian MiG 21 inside a hangar at Area 51. The CIA borrowed one from the Mossad, reverse engineered it, and then flew it in mock air battles over the Nevada desert. This secret program, which took place in the winter of 1968, was called Operation Have Doughnut and gave birth to the Navy"s fabled Top Gun program. (Collection of Roadrunners Internationale/U.S. Air Force) (Collection of Roadrunners Internationale/U.S. Air Force)

Apollo astronauts trained on the subsidence craters at the Nevada Test Site before they went to the moon. Ernest "Ernie" Williams was their tour guide; he helped CIA engineers locate the original water spring at Area 51. (Department of Energy) (Department of Energy)

Astronauts study the geology on the atomic craters while carrying mock-ups of s.p.a.ce backpacks and other gear. (Department of Energy)

Richard Mingus worked security at Area 51 and the Nevada Test Site for decades. He is seen here during weapons training in 1979. (Collection of Richard Mingus/National Nuclear Security Administration) (Collection of Richard Mingus/National Nuclear Security Administration)

A Predator drone on the tarmac at Creech Air Force Base, Nevada, June 2008. Located just thirty miles south of Area 51, the airstrip here was formerly called Indian Springs. It is where atomic sampling pilots once trained to fly through mushroom clouds; where Dr. Edward Teller, "father of the H-bomb," used to land before atomic bomb tests; and where Bob Lazar says he was taken and interrogated after getting caught trespa.s.sing on Groom Lake Road. (U.S. Air Force/Steve Huckvale) (U.S. Air Force/Steve Huckvale)

From Creech Air Force Base, Nevada, U.S. Air Force pilots fly drones over Iraq and Afghanistan using remote control. (U.S. Air Force/author collection) (U.S. Air Force/author collection)

Site of former EG&G offices on the edge of downtown Las Vegas as it looked in 2009. (Author collection) (Author collection)

Operation Hara.s.s and the search for the Horten brothers netted this sketch of a possible advanced Horten aircraft design. (Department of Defense) (Department of Defense)

Walter Horten holding a scale model of the Horten 10B in Baden-Baden, Germany, in 1987. (Collection of David Myhra) (Collection of David Myhra)

Reimar Horten in Argentina, 1985. (Collection of David Myhra) (Collection of David Myhra)

The Operation Crossroads 1946 commemorative yearbook depicts the Ros-well Army Air Base as the military facility from which the opening shot in the Cold War was fired. (Collection of Richard S. Leghorn/Army Air Forces (Collection of Richard S. Leghorn/Army Air Forces)

ABOUT THE A AUTHOR.

Annie Jacobsen is a contributing editor at the Los Angeles Times Magazine Los Angeles Times Magazine and an investigative reporter whose work has also appeared in the and an investigative reporter whose work has also appeared in the National Review National Review and the and the Dallas Morning News Dallas Morning News. Her two-part series "The Road to Area 51" in the Los Angeles Times Magazine Los Angeles Times Magazine was widely read. A graduate of Princeton University, Annie Jacobsen lives in Los Angeles with her husband and two sons. was widely read. A graduate of Princeton University, Annie Jacobsen lives in Los Angeles with her husband and two sons.