April 24, 1771 - The Japanese island of Ishigaki was devastated by a massive tsunami wave on this day. Triggered by a 7.4 magnitude earthquake in the ocean, a 279-foot wall of water slammed into the island. It was the highest tsunami wave ever recorded.
The wave was so powerful it carried an 830-ton block of coral a quarter mile inland. The odd monolith has stood there ever since.
Vast sections of the island were swamped by the tsunami and over 13,000 people were killed. Many others died on the surrounding islands.