But when World War One started they became weapons. Pilots could spy on enemy ... So a microphone was invented that you could use underwater on a ship to hear if any U-boats were nearby.

But when World War One started they became weapons. Pilots could spy on enemy ... So a microphone was invented that you could use underwater on a ship to hear if any U-boats were nearby.

The Organisation for the Prohibition of Chemical Weapons (OPCW), a global watchdog ... is an oily substance which was widely used during World War One. It causes irritation of the lungs, eyes ...

Trench raiding clubs were homemade melee weapons used by both the Allies and the Central Powers during World War I, so I thought that we should make our own! DiesInEveryFilm Customs - WW1 Weapons ...