Technological advances in the weapons of war were rapid during the 20th century. During World War I, inventions included the tank and the fighter aircraft. At sea, one of the major advances in military marine technology happened before the war, with the building of the battleship Dreadnought.

During World War II, the Germans used a new type of warfare, known as blitzkreig (lightning war). In the United States, the atomic bomb was invented.

The first atomic bomb exploded in an experiment in New Mexico in July 1945. A month later, atomic bombs were used to end World War II. Atomic bombs were dropped on Japan, killing about 130,000 people. Many people suffered effects, such as radiation and burn injuries. This bomb was used to bring the war against Japan to catastrophic end.

*Both the British and the French armies experimented with tanks during World War I. These armored vehicles were first used in the Battle of Cambrai in 1917.