The mystifying Coral Castle, created in secret by an architectural genius, Edward Leedskalnin. From 1923 to he single-handedly carved over tons of coral rock into a castle near Miami, and took the secrets of his construction process to his grave.
Mysteriously constructed single handedly by Edward Leedskalnin is the Coral Castle. Built in it is the sole modern megalithic site with some of its large coral 'stones' weighing up to 30 tons. The "black box" topping the tri-pod has never been found.