It's exactly what it sounds like, and yet it's so much more. Geologically speaking, the Giant Rock, located in California's Mojave Desert, is roughly seven stories high and covers almost 6,000 square feet. Some say it is the largest free-standing boulder in the world.

While the rock has been a Native American spiritual site for thousands of years, the modern back story of the boulder begins in the 1930s, when a German immigrant and miner named Frank Critzer met a pilot named George Van Tassel. They became friends and Van Tassel loaned Critzer 30 dollars to buy mining equipment. Critzer then dug out a 400 square foot home for himself directly beneath the the giant rock. This made the locals think he was crazy but since he was known to point a shotgun at those who approached his underground home, no one inquired further. In addition to being a notoriously gruff customer, Critzer was also a radio enthusiast, and is said to have set up a radio antenna on top of the rock for better reception.

Unfortunately, his German origin and radio antenna led to suspicions of his being a spy during World War II and a police raid was made on his cavern. While his exact cause of his death is still unknown, legend holds that when authorities attempted to extricate Critzer by shooting tear gas canisters into his cave, one accidentally ignited a small store of explosives (for mining) and blew the peculiar loner to smithereens. As it turns out, Critzer was not a spy after all, but just what he seemed: a eccentric who wanted to be left alone to live, quite literally, under a rock.

Something about Critzer's death resonated with his friend Von Tassle. Upon hearing of his friend's death, Van Tassel, a high-school dropout who had become a pilot, went to the boulder and reopened an old airfield at the Giant Rock in the 1950s, naming it Giant Rock Airport. Van Tassel's war friend Howard Hughes, for whom Van Tassel was a test pilot, is said to have flown there just for a slice of Van Tassel's wife's pie.

In addition to being an aviator, Van Tassel was also a believer in alien life. In 1952 Tassel began holding meditation sessions in Critzer's old home under the Giant Rock. Here, Van Tassel believed he was receiving vital information from alien sources for the construction of a fantastic machine. The body, Van Tassel learned from his alien sources, was an electrical device, and aging was caused by a loss of power. Van Tassel claimed to have even been transported an alien space ship, where he met a wise group of aliens known as the "Council of Seven Lights." Tassel said this extraterrestrial meeting, along with ideas from scientists such as Nikola Tesla, inspired the construction of a building/device which was to be a "rejuvenation machine." It was dubbed "The Integratron."

Van Tassel held popular UFO conventions known as the "Giant Rock Spacecraft Conventions" on his property for over 20 years to help raise money for the Integron's construction. The domed structure, built without nails over a period of 34 years, was said to be capable of collecting up to 50,000 volts of static electricity from the air in order to charge the human body. Unfortunately, Tassel suffered a heart attack before its "final" completion, giving rise to a host of conspiracy theories. There were plans to turn the Integron (http://atlasobscura.com/places/integratron) into a Disco, but instead today it is a tourist attraction which gives visitors a relaxing "sound bath."

Long before Van Tassel or Frank Critzer were around, the Giant Rock was also been a spiritual site for thousands of years, used by Native American tribes in ceremonies and prophecy. Hopi shamans have suspected since the 1920s that the future of the 21st century would be foretold at the Giant Rock, based on how the rock cracked. In February 2000, a giant chunk of the rock did indeed break off. Spiritual leader Shri Naath Devi interpreted the break in a positive light: "the Mother had opened her arms to us, cracking open her heart for the whole world to see." It is speculated the break was the result of fires burned under the giant rock in what was once Frank Critzer's underground home.

We explored the Giant Rock on Obscura Day - March 20th, 2010. Photos, stories and more here