One weapon helped Alexander the Great lead the underdog Macedonians to defeat the once invincible Persian Empire. Another helped commoners take down experienced knights from their horses, revolutionizing European warfare in the Middle Ages. And another, used today by guerrilla fighters and terrorists, has claimed more victims than nuclear bombs. Examine three weapons that can cause immense damage with very little training: the pike, the crossbow, and the AK-47 rifle. Discover the secrets behind their effectiveness.