Greenwich is situated on the south shore of a sharp bend in the River Thames, just southeast of the City of London and is part of Greater London. Here is located the world famous Royal Observatory where the Prime Meridian, dividing East and West Longitude, was defined by international agreement in 1884. In this detailed portion of a larger area photographed by the crew of the International Space Station on May 8, 2000, the location of the Observatory itself is roughly the small, light area in the northern, wooded part of Greenwich Park. The River Thames with its port facilities and industrial sites winds its way, left to right, across the scene. The large, white, circular structure is the Millennium Dome. Over 1 km in diameter and 50 m high, it was built as an exhibition center to commemorate the new millennium, which chronologically began at the Prime Meridian.