The Laser Interferometer Gravitational-Wave Observatory (LIGO) Project to develop a terrestrial astronomical observatory for gravitational wave detection is being developed by a Caltech-MIT collaboration. This effort is complementary to plans for detection in space, as it is sensitive to a higher frequency band (10Hz to 10kHz) and therefore different gravitational wave sources. (C) 2000 COSPAR. Published by Elsevier Science Ltd.