The base is about 80 miles north-northwest of Las Vegas, on the eastern edge of the USAF's Nellis training range. The name "Area 51" originated with the Atomic Energy Commission, which operates the Nevada Test Site to the west of the base, and divided the land around the site into numbered regions for planning and fallout tracking. The base is also called Groom Lake, the original name of the dry lake bed on which the runways are built, and has sometimes been nicknamed "the Ranch". There is some evidence that, officially, it is a detachment of the USAF Flight Test Center at Edwards AFB.

The USAF coyly admits to the existence of "facilities" within the Nellis range. No official, unclassified documents can identify the base: even accounts of events 40 years ago refer to it as "a remote location." The fence line is protected by seismic and infra-red sensors and contract security officers ("Cammo Dudes"). Since the Air Force seized two excellent vantage points in 1995, the closest public land from which you can see the base is Tikaboo Peak, 20 miles away.

In 1954, Lockheed Skunk Works founder Kelly Johnson and test pilot Tony LeVier had to find a place where the CIA's U-2 spyplane could be tested in secrecy. Area 51 was remote, had a hard lakebed, and was in the shadow of nuclear tests. LeVier made the first U-2 flight from Area 51 in July 1955, and the early U-2 pilots (including Frank Gary Powers) were trained there. The base was closed when the U-2 was unveiled later in the decade, but was reactivated and expanded in 1960-62 to handle the Lockheed A-12, first of the Mach 3 Blackbirds. Later in the decade, the 4477th Test & Evaluation Squadron, the "Red Hats", moved in to test some "liberated" Soviet aircraft, an activity that continues to this day.

The first real stealth aircraft, Lockheed's Have Blue prototype, was flown from Area 51 in December 1977. Its operational descendant, the F-117 stealth fighter, flew from the base in 1981. Northrop's strange-looking Tacit Blue stealth reconnaissance aircraft was flown from Area 51 between 1982 and 1985.

That is the one-heckuva-lot-of-billions-dollar question. Under the Reagan and Bush administration, more land around Area 51 was closed, the USAF took it over from the CIA, one runway was extended to 20,000 feet and another one was added, and many new buildings were added. Spending on USAF black-world programs ran at $15-20 billion per year in that time, and remains at a healthy $12 billion a year. In spite of that fact, not one program tested there since 1985 has been disclosed. Best guesses: prototypes (and, possibly, short production runs), of next-generation stealth aircraft, high-speed aircraft, and unmanned vehicles.

Two reasons. One of these is to conceal evidence of technical breakthroughs from potential adversaries. If anyone had seen Have Blue in 1977, they would have realized that the U.S. was trying to build an airplane with the radar image of a BB pellet. As it was, most of the world did not think that was possible, so they could not begin to design an effective countermeasure. The other reason is to protect high-risk projects from Congress, Mike Wallace, and Pentagon and industry conservatives.

"Janet" is the call-sign of the Boeing 737s that shuttle workers from a private terminal at Las Vegas airport to Area 51 and the former F-117 base at Tonopah. The south side of the Luxor Hotel here has a good view of the terminal. Other routes to the base include a paved highway through the Test Site and an unimproved road from Nevada State Highway 375.

Nobody said a word about aliens at Area 51 until 1989, when a Las Vegas resident, Bob Lazar, claimed that he had worked on a secret project to "reverse engineer" disc-shaped alien craft that had crashed in the United States at a facility at Papoose Lake, south of Area 51. Upon this foundation, UFO enthusiasts have built a vast edifice of theory involving black helicopters, abductions, underground bases, the Trilateral Commission and the Knights Templar. This, in turn, has spawned an industry. The Little A-Le-Inn in Rachel has prospered on sightseeing traffic. Radio and TV (Art Bell and Sightings) paved the way for Hollywood (Independence Day). Even the state government has got into the act, naming Nevada 375 as the Extraterrestrial Highway. You can believe all this if you wish, but remember that there has been weird stuff in the sky around Area 51 for 40-plus years - and that there is a strictly terrestrial explanation for it.

By Bill Sweetman