The First World War was the first truly global conflict. From 1914 to 1918, fighting took place across several continents, at sea and, for the first time, in the air.
The Battle of Balaklava in 1854 witnessed one of the most famous acts of battlefield bravery and one of the most infamous blunders in military history.
The Second World War (1939-45) was the bloodiest conflict in human history. It split the world's nations into two opposing military alliances - the Allies and the Axis Powers.