Akkadō

Akkadō (安家洞), located in Iwaizumi, Iwate Prefecture in the Tōhoku region of northern Japan, is the longest limestone cavern in Japan, with a measured length of 23702 m. The cave system was designated as a Natural monument by the Japanese government in 1980. Since 1991, a portion of the caverns have been open to the public for part of the year.

Outline
There are flowstones and a subterranean lake.

Access

 * Iwaizumi Town Bus
 * From/to Iwaizumibashi