Leros was regarded as a corridor of the Mediterranean and was first under the fascist regime of Italy for 31 years, during which the Italians had established strategic naval bases on the island. During the Second World War, Leros was heavily bombed by the British Royal Air Force and later on, it suffered heavy aerial bombardment and assaults from German troops.

The War Museum is housed in an old tunnel that was built by the Italians during the Second World War. It hosts a fine collection of exhibits, including guns, bombs, helmets, uniforms as well as documentation and other audio-visual material relating to the battle of Leros. The museum is open to visitors in the morning.