TheLusitania was a ship that carried goods to the British and French. The Germans did not like this because they were in a war and they did not want their opposite to have goods. The Lusitania sank because of a German submarine.But before they shot it the Germans tried to gain control of it using their navy. But the British managed to keep the German navy in check. The Lusitania sunk in 20 minutes after being struck. The Germans declared the seas around Britain to be a war zone. And any Allied ship that came through there they would sink It.
Cause
You better get off of my ship you and your navy.
The Sinking of the Lusitania May 7, 1915.
We are going to take your ship down.
One effect is that the killing of innocent people outraged the people of many countries.The Allied side got more and more support from other countries to defeat germany. And the people hated Germany for this and they were goingto get them back.