A view of Istanbul as taken from the International Space Station. The metropolis of 15 million occupies both sides of the entrance to the narrow, 32 km- (20 mi-) long Bosporus Strait connecting the Mediterranean and Sea of Marmara (south, on the right) to the Black Sea (north, on the left). When this image was taken, strong currents carried turbid coastal waters from the Black Sea through the Strait and into the Sea of Marmara. The sinuous waterway and harbor on the western shore are known as the Golden Horn. Image courtesy of NASA.