Kamioka Gravitational Wave Detector
The Kamioka Gravitational Wave Detector (KAGRA) is a large-scale physics experiment designed to detect gravitational waves predicted by the general theory of relativity. It is located underground at the Kamioka Observatory which is near the Kamioka section of the city of Hida in Gifu Prefecture, Japan.
Source: Wikipedia — Kamioka Gravitational Wave Detector (CC BY-SA 4.0)