Sediment-laden Galveston Bay, which occupies the drowned mouths of the Trinity River and the San Jacinto River, is featured in this south-southwest-looking, low-oblique photograph. The bay presently averages 12 feet (4 meters) in depth; however, at the end of the last ice age, melting glaciers caused the sea level to rise approximately 400 feet (122 meters). A ship channel allows large merchant ships into the Port of Houston, the third-busiest port in the United States. Apparent are Trinity Bay (center of the photograph); the mouth of the Trinity River (bottom left) with its vast load of sediment at the north end of the bay; sediment-filled, circular Lake Anahuac east of the Trinity River mouth; southeast Houston and the small port city of Baytown; and Galveston near the southern portion of Galveston Bay (top center).