The first image is of Picket’s Charge at the Battle of Gettysburg, in the Civil War in 1863. The July 3rd artillery bomb bardment was likely the largest of the war, with hundreds of cannons from both sides, firing across the battle lines for one or two hours.
Although the attack is popularly called a "charge", the men marched deliberately in line, to speed up, and then charge only when they were within a few hundred yards of the enemy.