Laser Interferometer Gravitational-Wave Observatory (LIGO) | Britannica
LIGO detects first ever gravitational waves – from two merging black holes – Physics World
Looking for distortions in Spacetime - located near the Hanford Reach nuclear site, the LIGO (Laser Interferometer Gravitational-Wave Observatory) research facility uses lasers fired down two 4km-long tunnels to measure gravity waves,
Video | Most Precise Ruler Ever Constructed | LIGO Lab | Caltech