Details the change in military strategy towards "Trench Warfare" and the events leading up to the Siege of Petersburg. The Siege lasted nine months in which Union forces assaulted Petersburg unsuccessfully and then constructed trench lines that eventually extended over 30 miles. Numerous raids were conducted and battles fought in attempts to cut off the Richmond and Petersburg Railroad. Lee finally gave in to the pressure and abandoned both cities in April 1865, leading to his retreat and surrender at Appomattox Court House.