Eward Leedskalnin was born in Riga, Latvia in 1887. He was a small man, around five and a half feet tall and barely 100 pounds, but he built a castle by himself completely out of coral. It took him decades, but he did it… and he disassembled, moved it, and built it all again!

The story goes that Leedskalnin fell in love with Agnes Scuffs, a girl ten years his junior, in Latvia. They were to be married, but the teenager broke off with him the night before the wedding, apparently due to the age difference. He referred to her as “Sweet Sixteen” for the rest of his life. The Coral Castle was supposed to be a monument to Scuffs, although some theorize that “Sweet Sixteen” was a code name for his unified theory of the universe or the secret of how he built the castle. Leedskalnin later wrote an essay entitled A Book in Every Home, which includes his explanation of how teenage girls should not be “soiled” by consorting with boys their own age, a telling reference to his own love life.

Leedskalnin wrote about his theories of magnetism and electricity, including what he called the Perpetual Motion Holder. He claimed to have discovered the secret of ancient pyramid construction, although he didn’t divulge that information. He could be pretty cryptic when he wanted to be. He wrote several booklets that he sold, promising to divulged the magnetic secrets of the physical world.

Leedskalnin immigrated to the United States and worked in the lumber business in various locations. After contracting and recovering from tuberculosis, he moved to Florida. He began building his castle in Florida City in 1920, excavating coral from his own property. He worked on his masterpiece for thirty years, but would not let anyone watch what he did. Leedskalnin worked at night, only when he was sure no one was around. Some have theorized that the small man excavated, moved, carved, and lifted the stones using his scientific magnetic discoveries. Others say he supernaturally made the boulders lighter. Leedskalnin did not dispute either theory. However, there are a few photographs that show Leedskalnin using simple machines and general principles of engineering to move the massive stones.

Leedskalnin took the coral castle apart in 1936 and moved it to Homestead, Florida. Supposedly a subdivision was to be built in the area. Possibly Leedskalnin looking for more privacy. It has been reported that an attack on Leedskalnin by treasure-seeking thugs precipitated the move. He hired a truck and driver, but never let the driver load the truck or even watch as Leedskalnin loaded the massive coral fixtures. After the material was unloaded, Leedsskalnin resumed his solitary work to put it back together.

When Leedskalnin died of stomach cancer in 1951, a plaque was found in his bedroom inscribed with this cryptic statement: “The Secret to the Universe is 7129 / 6105195″, which disputes the simpler and better-known equation of 42. He left other writings, but nothing that detailed how he built the castle.

The entrance to the Coral Castle is a swinging gate made of a nine-ton slab of coral. It is balanced so well that you can move it with the touch of a finger -or was, until it fell off its pivot in the mid ’80s. It took a crew with heavy equipment to reset it, and it has never been as well-balanced as when Leedskalnin set it himself.

A thirty-ton “telescope” stands 25 feet high with an aperture that is perfectly aligned with the North Star. (image credit: Flickr user paparutzi)

Leedskalnin also created a sundial that tells the time accurately within two minutes. The sundial stands across from the “Moon Fountain” which features carvings of crescent moons  (image credit: Flickr user chrisheuer)

This heart-shaped coral table weighs 5,000 pounds!

Coral Castle is on South Dixie Highway in Homestead, Florida. It is open to the public daily and can even be rented for weddings and other occasions. A trip to the castle inspired Billy Idol to write the song “Sweet Sixteen”.

Someone’s built a candy castle
For my sweet sixteen.
Someone’s built a candy house
To house her in.

See also: 7 Lifelong Personal Projects and The Watts Towers. Thanks to the many mental_floss readers who suggested this topic!