One of the innovative techniques the North used to its advantage during the Civil War was the reconnaissance balloon. Protagonist for its use was Professor Thaddeus S. C. Lowe who personally proved its effectiveness by using it to diagram Confederate positions. The balloon's weaknesses were its slow maneuverability and vulnerability to ground fire.

In March of 1862, General George McClellan sent Professor Lowe floating above the Union line in the Intrepid, a tethered hydrogen observation balloon, to study Confederate positions at Yorktown, Virginia. In this image, Confederate soldiers are desperately trying to shoot down the balloon with muskets and rifled cannons.

- Tom Lovell