Union Soldiers at Petersburg - compares favorably with scenes in Cold Mountain 
 The Crater
The Spencer Repeating Rifle  
Sherman's march through the Carolinas from 
Joe's SC Railroads Research Page  which is a pretty cool site done by a history and rail enthusiast in South Carolina. 
The Line of Lee's Retreat
The McClean House where Lee surrendered the Army of Northern Virginia to Grant. (At least a re-creation / restoration) Near Appomattox Courthouse, VA.
 Ford's Theater at the time of Lincoln's assassination on April 14.
 Capture of Jefferson Davis