In March 1862, Union steamboats fought the currents of the Tennessee River to carry an invading army deep into the Confederacy. At the height of the Union occupation, transports and gunboats lined both sides of the river four and five deep. Men carried on these ships fought at Shiloh and later helped capture the Confederate rail center at Corinth, Mississippi. For the rest of the war, Union gunboats patrolled the Tennessee, preventing the Confederates from building artillery batteries, skirmishing with Southern shore parties, and occasionally taking retribution on riverside towns. By the war's end, only chimneys marked the sites of some of the valley's oldest settlements, while Savannah suffered little damage, likely because of its numerous Union sympathies. The wooden gunboat Lexington, like its sister ship U.S.S. Tyler, fired on Confederate troops during the Battle of Shiloh, and shells from these gunboats harassed the Confederates during the night of April 6-7 as gunboats stood watch and transports shuttled troops across the Tennessee River at Pittsburg Landing.