"High dwellings are the peace and harmony of our descendants. Remember the calamity of the great tsunamis. Do not build any homes below this point," reads a four-foot high stone slab in the hamlet of Aneyoshi, in the Iwate Prefecture, in Japan. Residents who heeded the advice from their ancestors kept their tiny village of 11 households safely out of reach of the deadly tsunami that stuck Japanese coast in 2011. The waves stopped just 300 feet below the stone.

All over the coast of Japan, there are hundreds of so called Tsunami Stones with warning messages and advice, some more than 600 years old. These flat stones, some standing up to 10 feet tall, collectively form a crude warning system for Japan, whose long coasts along major fault lines have made it a repeated target of earthquakes and tsunamis over the centuries. Many carry simple warnings to drop everything and seek higher ground after a strong earthquake. Others, such as the ones in Aneyoshi, specifically instruct where to build homes and where not to. Many stones lists names of the dead or past death tolls as a grim reminders of the waves’ destructive force. Unfortunately, in the bustle of modern life, many of these ancient warnings were forgotten or simply ignored.

A tsunami warning stone tablet erected in 1933 on a hillside in Aneyoshi in Japan’s Iwate prefecture. Photo credit