The year was 1863; December 13th, the setting is Fredericksburg, Virginia. The bloodiest ground in North America is where one of the most valuable lessons on cover and concealment was learned. There, the union, preparing to cross the Rappahannock River. This was a planned attack on the city where 75,000 confederate soldiers sat on a line of hills to the left in particular, an area known as Marye’s Heights.