Yoshimi Hundred Caves

The Yoshimi Hundred Caves is a cluster of corridor-type kofun tombs dug in artificial caves in a tuff cliff of located in the town of Yoshimi, Saitama, in the Kantō region of Japan. It was designated as a National Historic Site on March 7, 1923. The Schistostega luminous moss growing at the site was also designated as a Natural Monument of Japan on November 30, 1928. The site is part of Hiki Hills Prefectural Natural Park.

Source: Wikipedia