There is a cave into the wonderful sugi trees and clean air. The cave has pure water. The water coming through racks is designated as Japanese water "best 100".
In mythology, Sun Goddess Amaterasu Oomikami hid into the cave to discipline his brother Susanoono Mikoto. The world without Sun Goddess was covered with darkness. It is said that this cave is a stage of that saying.
Also, in the atmosphere like the mythology, you can experience ascetic practice by sitting under a waterfall.