6A British soldier inside a trench. TrenchesA British soldier inside a trench.
7Battles to Know Marne Somme & Verdun 1st trenches bloody little ground gained
8Why did the US enter the war in 1917? Germany’s unrestricted submarine warfare1915: sinking of Lusitania: halted1917: resumedZimmermann TelegramGermany offered Mexico US territory if they joined the German cause
9Why was WWI so destructive? trench warfarenew technologies:tankpoison gasmachine gunairplanesubmarine
10Verdun: Before & AfterCloister of the Hotel la Princerie (France) – before and after the battle.
11Tank 1916: tank warfare introduced by France/GB 1917: France & GB used 1500 tanks eachA German tank.
12Poison Gas German soldiers wearing gas masks. The Germans introduced the use of poison gas in warfare in 1915.