Marines serving with the 13th Marine Expeditionary Unit for San Francisco Fleet Week 2012 march along the 50-yard line on Candlestick Park for a rehearsal for the pregame show at the 49ers game, Oct. 7, 2012. U.S. Marines, sailors, coast guardsmen and members of the Royal Canadian Navy marched on to the field to salute during the singing of the national anthem. The service members received a standing ovation as they left the field.