Ryusendo Cave is one of the three largest limestone caves in Japan and was designated as a national natural monument in 1938 as "Iwaizumi Yungkutsu and Bats.

The total length of the caves, which are still being investigated, is estimated to be over 5,000 meters.

The total length confirmed by the latest survey is over 4,088m, with a height difference of ±195m.

About 700 m of the site is open to the public as a sightseeing course, with the highlights being the mysterious cave space that stretches in a straight line from the entrance and the underground lake with abundant clear water and a "dragon blue" glow.

Visitors can tour from the first underground lake, which was discovered during a survey in the 1930s, to the third underground lake, which boasts a maximum depth of 98 meters.

The mineral-rich water from Ryusendo, nurtured by the surrounding forest area, is used as the water supply for the town of Iwaizumi and is also popular as a souvenir.

The Kikugashira bats, which live in Ryusendo, are often seen here, and five other bat species have been confirmed to inhabit the caves, including bats that visit the caves to overwinter.

Do not touch them and observe them gently!

You can also enjoy the Ryusendo New Cave Science Museum, which is accessible with a common ticket with Ryusendo.

This is a science museum using a natural cave with approximately 200 meters of limestone caves open to the public.

Located right across from the entrance to Ryusendo, the museum features stalactites of various shapes nurtured in ancient strata.

Ruins that are thought to date back to the early Jomon period have also been found, and earthenware, ornaments, shells, and other artifacts have been excavated.