Centennial Olympic Park was designed as the "town square" of the Olympics, and thousands of spectators had gathered for a late concert by the band Jack Mack and the Heart Attack. Sometime after midnight, Rudolph planted a green U.S. military ALICE pack (field pack) containing three pipe bombs surrounded by nails underneath a bench near the base of a concert sound tower. He then left the area. The pack had a directed charge and could have done more damage but it was tipped over at some point. It was the largest pipe bomb in U.S. history, weighing in excess of 40 pounds. It used a steel plate as a directional device. Investigators were later to tie the Sandy Springs and Otherside bombs together with this first device because all were propelled by nitroglycerin dynamite, used an alarm clock and Rubbermaid containers, and contained steel plates.
Security guard Richard Jewell discovered the bag and alerted Georgia Bureau of Investigation officers; 9 minutes later, Rudolph called 911 to deliver a warning. Jewell and other security guards began clearing the immediate area so that a bomb squad could investigate the suspicious package. At 1:20 AM, the bomb exploded.