From The Crop Circle Ship Wiki
Coral Castle is a stone structure created by the Latvian-American eccentric, Edward Leedskalnin, north of the city of Homestead, Florida at the intersection of U.S. Route 1 (South Dixie Highway) and Southwest 288th Street (Biscayne Drive). The structure is comprised of numerous megalithic stones (mostly coral), each weighing several tons.
Ed claimed to know how the Ancient Egyptians built the pyramids, and that he used this knowledge to construct Coral Castle. As far as is known, Ed never shared the secret with anyone, until he passed away in 1951.
 The secret code
On the radio show Coast to Coast AM (April 3rd, 2007), Joe Bullard (webmaster of http://www.waitingforagnes.com) mentioned that Ed Leedskalnin had made reference to a certain sequence of numbers as the 'secret to the universe, as shown below.
The secret code is 7129 6105195
"It is worth noting that the oldest known number system, from the fertile crescent cultures that predates even Chinese and Egyptian, used base 6 discovered through astronautical calculation rather than base 10." Source: http://www.aprille.net/opinions.html
The ancient Sumerians were also known to use a base 6 number system.
 Hexagons and Tetrahedrons
On Coast to Coast AM (on July 12th 2007), Richard Hoagland mentioned the following regarding Coral Castle: "I wandered around, and then she [Robin] noticed on the wall one of the things that Ed Leedskalnin had left which was basically a hexagon with two inscribed tetrahedron in it over his outdoor bathtub which is kind of like a clear signal..."
 External links
 Also see