In days of old, if your army had to take on a huge stone castles there was only one option: bunker busting siege weapons like the giant crossbow known as the Ballista and the fearsome Trebuchet! These weapons hurled rocks and flaming kegs to cause mayhem and smash through walls. Today the siege tradition continues, with our military using high-explosives to blow the bad guys out of their foxholes. First, Gunny let's loose massive boulders from an ancient trebuchet catapult against an enemy castle. Then he gets his hands on some old-style gunpowder and recreates the big bangs that were used to bring down enemy bunkers, all the time instructed by committed experts who revel in the history of these amazing weapons. Gunny also visits today's bunker busters--military engineers who bust under, over, and into enemy strongholds.