Abukuma-do (阿武隈洞 - 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 (釜山鍾乳洞). It was designated a natural heritage of the town on February 7, 1971 and renamed Abukuma-do 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.