Akkadō

What it is

• Akkadō is a limestone cave in Iwaizumi Town, Iwate Prefecture.
• It is the longest cave in Japan, 23,702m in total length.
• Designated as a National Natural Monument.
• It is a geosite of the Sanriku Geopark.

What to see

• The main cave branches into east and west.
• Numerous branch caves extend from the main cave.
• Giant flowstones, underground lakes, and shield groups.
• The publicly accessible area extends 700m to Senmaizara.
• Helmets are provided at the entrance.
• The cave has an average temperature of 8°C.

When to go

• Open from mid-April to late November each year.

Notes written by Japan Gems from facts in Japanese Wikipedia.