Ryugado, in Kochi prefecture, is one of the Three Greatest Limestone Caves of Japan and has been designated a National Historic Site, as well as a National Natural Treasure. Earthenware from the Yayoi Period (300 B.C.-A.D. 300), evidence of cave dwelling, was uncovered in this 4-km-long cave.
Avastatud: 16-1-1993 Avastamiskoht: Geisei Avastajad: Seki, T.