Siege mounds were mounds or ramps built out of dirt, rubble, and timbers. They were designed so that soldiers could batter down a city’s walls and fortifications. The Assyrians were the first to use wheeled towers with these mounds. Protected inside the tower as it was moved up the ramp to the wall, the soldiers could then exit the tower and invade the city. A siege mound can still be found today at Masada.