Volunteer groups representing Union and Confederate troops provide a weekend of "living history" at Gettysburg National Military Park. This weekend it`s the 20th Maine Infantry, U.S. Sharpshooters, and the Frederick Ladies Society camp and programs at the Pennsylvania Monument, Auto Tour Stop No. 12, the 20th Maine Hospital at Meade's Headquarters, the 2nd Maryland Infantry, CSA will host a camp and programs at Pitzer Woods, Auto Tour Stop No. 6, and the 23rd Virginia Infantry camp and program at Spangler's Spring, Auto Tour Stop No. 13.