9Coral Castle, USA

In Homestead, Florida, lies a curious complex known as Coral Castle, constructed single-handedly by Latvian-American Edward Leedskalnin over 28 years. Without heavy machinery or assistants, he quarried, moved, and sculpted over 1,100 tons of coral rock.

How he accomplished this feat remains unknown. Leedskalnin never revealed his methods, cryptically stating that he understood the laws of leverage and magnetism better than most. Some even claim he had knowledge of anti-gravity.