GEO 600 is a gravitational wave detector located near Sarstedt, Germany. This instrument, and its sister interferometric detectors, when operational, are some of the most sensitive gravitational wave detectors ever designed. They are designed to detect relative changes in distance of the order of one part in 10−21, about the size of a single atom compared to the distance from the Sun to the Earth. GEO 600 is capable of detecting gravitational waves in the frequency range 50 Hz to 1.5 kHz. Construction on the project began in 1995.
Read more about GEO 600: Joint Science Run With LIGO, Claimed Link Between GEO 600 Detector Noise and Holographic Properties of Spacetime