Abukuma-do

Abukuma-do is a limestone cave located in Fukushima Prefecture, Japan. The cave was discovered on August 15, 1969, northeast of the city of Tamura. Visitors can traverse a 600-metre-long path inside the cave as well as a 120-metres-long exploration course to view the stalactites and stalagmites. Nearby Abukuma Cave is the smaller Irimizu Shonyu-do, discovered in 1927. The total length of the cave, including open to the public, is approximately 3,300m, which may be extended depending on future explorations. Each stalactite has taken more than eighty million years to form. The temperature inside Abukum-do has an average of 15 °C and the humidity is above 90%. The average temperature in the cave is around 14°c, although this temperature does not fluctuate greatly although in 1975 to 1977 the temperature was seen up to 15 to 17°c in summer in the summer. In winter the average temperature can be seen around 0 to 10°c near the entrance.