Abukuma-do

Abukuma-dō (Abukuma Cave) is a limestone cave located in Fukushima Prefecture, Japan.The cave was discovered on August 15, 1969, northeast of the city of Tamura and was originally named Kamayama Shonyu-do. It was designated a natural heritage of the town on February 7, 1971, and renamed Abukuma-dō on June 1,1973. Visitors can traverse a 600-metre-long path inside the cave as well as a 120-metre-long exploration course to view the stalactites and stalagmites. Each stalactite has taken more than eighty million years to form. Beyond the public areas lie about 2,500 metres of cave that are not open to the public. Nearby Abukuma Cave is the smaller Irimizu Shonyu-do (Irimizu Limestone Cave), discovered in 1927. Irimizu Limestone Cave was designated a National Natural Treasure on December 28, 1934. The temperature inside Abukuma-dō is approximately 15 °C and the humidity is above 90%.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).