CNN's Ben Wedeman has been up on the ridgeline overlooking Kalak, a ridgeline that's been pounded by coalition airstrikes during the last couple of weeks.
"It would take three or four hours to clear a ridgeline so soldiers could advance, " explains Lieutenant Colonel Matthew England of the Army's training and doctrine command, which develops equipment for soldiers.
For instance, the kiosk explains that Rothermel's deliberate perspective puts the viewer 125 yards from the copse of trees just below Cemetery Ridge in an area of the battle line known as "the Angle, " a jog in the stone wall defended by the Philadelphia Brigade.