The Massive Keyhole Tombs of Japan

Ancient Japanese rulers were buried in colossal, keyhole-shaped mounds visible only from the sky. These massive earthworks were constructed long before airplanes existed, leaving their true scale a secret for centuries.

These burial sites, known as Kofun, were built across Japan between the 3rd and 7th centuries. The largest examples rival the Great Pyramid of Giza in total volume. Because these sites are considered sacred imperial property, archaeologists have faced strict limitations on investigating them. This preservation has kept much of their history shrouded in mystery for over a millennium.