There is a huge boulder on a cliff in Tonga. Now we know how it got there.

Researchers say the Maka Lahi boulder was found more than 600ft from a rocky outcrop and was likely thrown there by a powerful wave 7,000 years ago. (Image courtesy of Martin Koehler, UQ)

A huge rock rising hundreds of feet over the edge of a cliff in Tonga was likely carried by an ancient tsunami, making it one of the largest wave-borne rocks on the planet.

Discovered in 2024 on the southern coast of the island of Tonga, Tongatapu, this boulder sits 656 feet (200 meters) from the edge of the cliff, 128 feet (39 m) above sea level. It measures an impressive 45.9 x 39.3 x 22 feet (14 x 12 x 6.7 meters) and weighs over 1,300 tons (1,180 metric tons).

It is the world's largest cliff-top boulder, first spotted by locals. “We were exploring the southern part of Tongatapu Island, looking at coastal cliffs for evidence of past tsunamis,” said lead author Martin Köhler, a scientist at the University of Queensland in Australia. “We were talking to farmers, and they directed us to this boulder.”