Ryusendo Cave

Ryusendo Cave is one of the Three Great Limestone Caves in Japan and a national natural monument. The portion of the cave which has been explored stretches over 3,100 meters; if unexplored areas are included, the entire cave is estimated to be over 5,000 meters in length.
You can take a tour of the cave, which takes about 30 minutes. In the cave, fresh spring water forms deep underground lakes; the most impressive is the third lake, with a depth of 98 meters and beautiful emerald-green water.

Image Provided by Iwate Prefecture