Armchair historians can tell you about the biggest surprise attacks ever and the impacts they had. Some of the greatest traps, ambushes, and shocking assaults have altered history’s trajectory.

To identify the biggest surprise attacks in history, 24/7 Tempo reviewed sources like History Collection, War History Online, Military History Now, NPR, Historic UK, Historynet, and Britannica. These attacks were often of great historical importance, and in many cases turned the tide of war. While this list is not meant to be a definitive list of every important surprise attack in history, it includes many of the most famous and historically significant ones. The battles are listed in the order in which they occurred.

Many of the attacks that achieved surprise were executed by a nation or political movement that was underestimated by its enemy. The badly mauled Continental Army of General George Washington shocked Hessian mercenaries employed by the British Empire at Trenton, New Jersey, on Christmas Day, 1776, giving the new nation a needed morale jolt. Nearly 200 years later, America thought the communists were a spent force in South Vietnam, until the Tet Offensive in 1968 showed that the enemy had plenty of fight left, suggesting to the American public that the war was unwinnable.

Superior tactics allowed the Greeks to defeat the Persian Empire at the naval battle at Salamis in the fifth century BC; Hannibal’s Carthaginian army to rout the Romans at Lake Trasimene 200 years later; and General Robert E. Lee to vanquish a larger Union army at Chancellorsville in 1863.

Surprise attacks are always a gamble, and sometimes that roll of the dice doesn’t pay off. Japan stunned the U.S. Pacific fleet at Pearl Harbor on Dec. 7, 1941, and destroyed many battleships and planes. But the victory was incomplete. The attackers left the docks and refueling infrastructure intact, and American aircraft carriers were out at sea – and in April of the following year, American B-52 bombers rained destruction on Tokyo in response. (These are the cities destroyed by the U.S.A. in World War II.)

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