Like the ancient wonders of Stonehenge or the Great Pyramids of Egypt, there is an incredible and mysterious creation right here in the United States. Coral Castle, in Homestead, Fla., just south of Miami, is an intricate rock garden made of enormous pieces of coral, many of them weighing several tons. But more amazingly, Coral Castle was built entirely by one man -- Latvian immigrant Ed Leedskalnin, who stood just 5 feet tall and weighed 100 pounds. To this day, no one knows how he did it. The castle is an extraordinary feat of engineering, and experts have puzzled over how Leedskalnin, who only had a fourth-grade education, constructed Coral Castle by himself. For example, how did this little man build a 9-ton coral gate constructed so precisely that you can push it open using one finger? There are many theories on how Leedskalnin accomplished this amazing feat. Some say he had help from extraterrestrials, others believe he discovered the secrets behind anti-gravity and levitation. Leedskalnin was a self-taught expert on magnetic currents, and one theory holds that he positioned the site to be perfectly aligned with Earth's poles to eliminate the forces of gravity, allowing him to move stones weighing several tons each. Even Albert Einstein couldn't figure it out.