Show this content while the ad loads.

1. The bolt-action rifle could fire 15 rounds a minute.
2. Machine guns needed 4 - 6 men to work them.
3. Large field guns fired bullets.
4. Mustard gas is yellow in colour.
5. The Zeppelin was a German airship.
6. The first tank was used at the Battle of the Somme.
7. Planes were first used for spying work.
8. A fight between two planes is called a catfight.
9. German submarines torpedoed supply ships.
10. The Lusitania was torpedoed in 1915.