From the start of the Great War, the name by which World War I was first known, British warships blockaded German ports. In this way Britain's navy prevented supplies from reaching Germany, causing severe shortages of food and other goods. The Germans retaliated with their submarines, called U-boats. After 1915, U-boats attacked both warships and merchant shpping carrying supplies to Britain. In May 1915, a German torpedo hit a British passenger ship called the Lusitania. The ship was carrying nearly 2,000 passengers, including many American. The sinking of the Lusitania was one of the factors that eventually drew the United States into the war.
Fact file
Poppies were in flower on many of the French battlefields of World War I. Today, artificial poppies are sold in Europe and the USA to raise money for war veterans.
resources: tell me why (Chancellor Press)
image 1: https://upload.wikimedia.org/wikipedia/commons/3/35/USA_bryter_de_diplomatiska_f%C3%B6rbindelserna_med_Tyskland_3_februari_1917.jpg
image 2: https://www.rafmuseum.org.uk/images/online_exhibitions/Signal-blitzkriegLG.jpg
