This radar image features Vietnam's Mekong Delta where the Mekong, the world's twelfth longest river, fans out into tributaries and empties into the South China Sea in Southeast Asia. Ho Chi Minh (formerly known as Saigon), Vietnam’s largest city and chief port, is visible as white in the upper right corner. The image was obtained by combining three Envisat’s Advanced Synthetic Aperture Radar (ASAR) acquisitions (9 January 2007, 13 February 2007 and 20 November 2007) taken over the same area. The colours in the image result from variations in the surface that occurred between acquisitions.