There was no nuke onboard, but it was enough to scare off the trio who were later visited by Men in Black to tell them to keep quiet.

The unusual shape of the A12, its reflective coating, and its propensity to race above commercial airliners at Mach 3 led to a flood of UFO reports in the 1960s.

Todayyou know it as the Lockheed A-12, a spy plane used to keep an eye on the Soviets and Chinese during the cold war and used during Vietnam to photograph Surface-to-Air missile sites while flying 80,000 feet above the ground.

But until the crash, no one without clearance had seen OXCART — at least not up close. At least 2,850 test flights were flown out of Area 51, and commercial airline pilots would occasionally spot the underbelly of the plane as it tore by at 3 times the speed of sound. The reflection of the all-black fuselage would glimmer, leading to reports of UFO sightings. When pilots would radio what they saw, the Men in Black would meet them on the ground to sign non-disclosure agreements.

The sightings raised alarm bells within the U.S. military itself — since the CIA wouldn’t reveal what it was doing, even to the Air Force. The flyboys started Project BLUE BOOK to log sightings by Nevada residents and others. 74,000 pages of records are on file in the U.S. National Archives, but searching for “OXCART” or “Area 51″ reveals zero search results. But the U.S. military wasn’t so convinced it was being watched by little green men: The General “Buck” Turgidsons of the Army and Air Force figured it was the Ruskies trying to incite panic amongst the populace.

Itwasn’t until July 2003 that the U.S. Government admitted the facility even existed, though they didn’t call it by its popular name, and only conceded it was an “operating location” near Groom Lake. Maps produced by the American government block-out the Nevada Test Site associated with Area 51 but it’s clearly visible on Google Maps.

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It’s about 100 kilometres northwest of downtown Las Vegas. The site is off-limits to both the public and even regular military air traffic.

While“shoot on sight” orders apparently exist, no known violent encounters have been reported. Usually the worst a nosy X-Files fan will endure is a few hours of heebie-jeebies at the hands of unnamed men, a hand-off to the Lincoln County Sherriff’s department, and a $600 fine.

While Stonehenge is often associated with druids and modern day nutjobs, the site was built during the Neolithic era –  the last of three parts of the Stone Age (Paleolithic, and Mesolithic predate this period).

“The” Stone Age is a term that bothers archaeologists. They’re quite cranky about it because groups exited this stage at different times. Their crankiness may also be associated with the fact they rarely find themselves in Indiana Jones-like situations.

Some groups technically remained within their Stone Age until they came across more advanced civilizations. Archaeologists want us to talk about “a” Stone Age — much like that jackass you work with who went around reminding everyone that the “21st Century” didn’t technically begin until 2001. Scientists are also cranky about us using “stone age” as a derogatory term.

While “Stone Age” is often a term used to describe the first use of stone based tools, it also represents social advances including living in groups. The Stone Age ends with the smelting of copper, the development of agriculture, and religion. I’m not kidding about that last part. Hence Stonehenge.

The Stone Age (screw you, scientists) age represents approximately 99% of Man’s time on the planet, or 23% if you’re a Scientologist.

Reconstruction of Homo habilis, the builders of Stonehenge

Reconstructino of Paranthropus boisei, the "Kramer" of the Stonehenge builders

The primary inhabitant of the Stone Age was Homo Habilis, a variation of modern day man which first appeared 2.5 million years ago. H. habilis may not be a direct ancestor, and we only figured that out in 2007. And he may not have been the first to use stone tools.

The “cave man” Homo Habilis was quite short, about 4′ 3″ tall. He also wasn’t the hunter we imagine. Fossil evidence suggests he was regularly eaten by a large scimitar-toothed predator cat the size of a jaguar called Dinofelis.

One other thing that made Habilis so advanced, was his voice box, permitting basic communication within groups and the first to argue about which way the toilet paper roll should go.

Habilis had a wacky neighbour, the Paranthropus boisei. This species lived alongside him between 2.6 million and 1.2 million years ago. With molars twice the size of ours, he’s sometimes referred to as “Nutcracker Man.” Despite the massive teeth, he primarily ate plants, not animals, and often entered a cave by sliding into the room announcing, “Hello, Jerry!”

Man, as we know him today, is a direct descendant of Homo erectus. This was the first hominin to leave Africa around 2 million years ago. He walked from the continent to Spain, Indonesia, Vietnam and, presumably in the hunt for discount merchandise, China.