Ryusendo Cave, which can be found in the
foothills of Mt. Urera-san at the east of
Iwate, is one of the three largest
limestone caves in Japan and is listed as
a natural monument. The precise length of
the cave is not known as nobody has
explored its full length - 2500 meters of
it has been explored to date. It was
confirmed sometime ago that there are many
tributary caves inside Ryusen-do Cave, two
of which are named Komori-ana (Bats Cave)
and Kameiwa-shido (Tortoise Rock Cave). As
the name Komori-ana suggests, there are
five different species of bats living in
Ryusen-do Cave and each species is listed
as a natural monument.
Inside the cave, there are a few
underground lakes that are filled with
spring water which flows into the lakes
from the very deep back of the cave. The
first three lakes are open to the public,
which are approximately 700 meters from
the entrance of the cave. The clarity of
these lakes is internationally recognized,
especially the third lake, the depth of
which is 98 meters. It glows emerald green
in an artificial light fascinating your
eyes with its mysterious beauty.