Kiyotsu Canyon Tunnel (清津峡渓谷トンネル) 清津峡渓谷トンネル
In 2018 Ma Yansong remade the tunnel: shallow water mirrors the canyon, 750 m.
The Kiyotsu canyon cuts through the volcanic rock between Tokamachi and Yuzawa; its walls of stone columns (柱状節理) earn it, together with Kurobe and Ōsugi, the title of one of the three great canyons of Japan, with official designation as a Place of Scenic Beauty (名勝) and a Natural Monument (天然記念物) since 1941. The visitor tunnel, dug to reduce the risk of landslides on the original path, runs for 750 metres to the Panorama Station, redesigned in 2018 by the architect Ma Yansong.
Niigata
清津峡渓谷