First off, it is difficult to imagine the scale of this formation. The Mahabharat was one of the largest wars ever fought, and armies used a scale of measure known as Akshauhini to measure strength. As single Akshauhini consisted of 21,870 chariots, 21,870 elephants; 65,610 cavalry and 109,350 infantry. Now, it is said that over the course of the war, 18-20 Akshauhini senas (armies) were killed. I do not have to do the calculations for you to figure out how huge the armies actually were. And this in a concentrated around the Kurukshetra, which is roughly 48 x 128 Km in area. That makes a very dense war.