Ryuokyo Canyon, located in Nikko National Park, became a powerful landscape as it is today when volcanic rocks that has been blown off by a submarine volcano were eroded by the flow of the Kinugawa River 22 million years ago.
This is the perfect place for hiking.
It is very cool even in summer, so you can spend a pleasant time.
Please check the access below.

• https://travel.tochigiji.or.jp/en/things-to-do/47/