U-Boat Campaign

28 July 1914 - 11 November 1918

The U-boat Campaign from 1914 to 1918 is the World War I naval campaign fought by German U-boats against the trade routes of the Allies. It takes place largely in the seas around the British Isles and in the Mediterranean.

Germany invades Belgium

3 August 1914 - 31 October 1914

Great Britain declares war on Germany, claiming that they invaded Belgium, a neutral country, on their way to invading France.

Russia attacks Germany and Austria-Hungary

17 August 1914 - 14 September 1914

The Battle of Stallupönen is fought between Russian and German armies. This is the opening battle of World War I on the Eastern Front.

Battle of Verdun

February 21, 1916 - December 18, 1916

The Battle of Verdun, held between the German and French armies, becomes the largest and longest battle of the First World War on the Western Front.

Battle of the Somme

1 July 1916 - 18 November 1916

The initial day of this battle, 1 July 1916, remains the most costly day in the history of the British army. It suffered almost 60,000 casualties, over a third of whom were killed. The name "Somme" has since become synonymous with slaughter.

US Joins WW1

April 6, 1917 - 11 November 1918

The American entry into World War I comes in April 1917, after more than two and a half years of efforts by President Woodrow Wilson to keep the United States out of the war.