Area 51 has been ground zero for conspiracy theorists for decades.

Flying saucers. Bug-eyed aliens. Staged moon landings.

The government hasn't helped alleviate speculation –- it doesn't even acknowledge that the military outpost exists. If it did, it would be deep in the Nevada desert about 100 miles outside of Las Vegas.

But now, National Geographic is providing the public with a rare glimpse inside the clandestine site. It recently published never-before-seen, declassified photos from 1963 of a military plane crash and its coverup by the government, according to its website.

"Area 51 was created so that U.S. Cold Warriors with the highest security clearances could pursue cutting-edge aeronautical projects away from prying eyes," National Geographic said. "During the 1950s and '60s Area 51's top-secret OXCART program developed the A-12."

Made by Lockheed Corp., the A-12 was a precursor to the SR-71 Blackbird spy plane. The futuristic-looking jet could tear through the skies at more than 2,200 mph at 80,000 feet.

Check out the photo above and here to see the A-12 without its ominous black paint. Instead, its silver titanium shines bright under the desert sun -- a stark contrast to the A-12 in front of the Science Center at Exposition Park.

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-- W.J. Hennigan

Twitter.com/wjhenn

Photo: Lockheed's A-12 at Area 51. Credit: Roadrunners Internationale via Pangloss Films