The Overland Campaign, the first big face-off between Generals Grant and Lee, opened on May 5th of 1864 when the first shots of the Battle of the Wilderness were fired. The campaign was considered closed after the Battle of Cold Harbor, when the two forces settled down into siege warfare at Petersburg. The Overland was one of the bloodiest campaigns of the Civil War. Both sides moved from the big battle and retreat format to constant fighting and trench warfare. It was a harrowing glimpse into the stalemate that would become World War I a few generations later.