| June 28, 1914 | Assassination | Archduke Franz Ferdinand is assassinated in Sarajevo, triggering the outbreak of war. |
| August 1914 | Outbreak of War | War was declared by the various countries involved. |
| October 1914 | First Battle of Ypres | The first battle of Ypres - October to November |
| December 21, 1914 | Air Raids | December 21, 1914 was the first German air raid on Britain |
| December 24, 1914 | Christmas Truce | Soldiers on both sides initiated an unofficial Christmas truce. |
| February 04, 1915 | Blockade of Britain | Germany begins using U-boats to attack British and neutral shipping. |
| April 22, 1915 | Second Battle of Ypres | The second battle of Ypres lasted from April 22 to May 25 and was the first instance of poison gas use by Germany. |
| April 1915 | Gallipoli | The battle of Gallipoli lasted from April to December of 1915. |
| May 07, 1915 | Sinking of the Lusitania | The British liner Lusitania was sunk by German U-boats. |
| February 1916 | Verdun | The battle of Verdun lasted from February to December of 1916. |
| May 31, 1916 | Jutland | The naval battle of Jutland lasted from May 31 to June 1 of 1916. |
| July 1916 | Somme | The battle of the Somme lasted from July to November of 1916. |
| February 01, 1917 | Submarine Warfare | On February 1, 1917, Germany resumed unrestricted submarine warfare. |
| January 16, 1917 | Zimmerman Telegram | A telegram from German foreign secretary, Arthur Zimmerman to Mexico was intercepted by the U.S. The Germans wanted Mexico to declare war on the U.S. |
| March 15, 1917 | Abdication | Tsar Nicholas II abdicates the throne. |
| April 06, 1917 | War Declared | The U.S. declares war on Germany. |
| April 09, 1917 | Vimy Ridge | The battle of Vimy Ridge lasted from April 9 to 12, 1917. |
| June 25, 1917 | U.S. Troops arrive in Europe | U.S. troops began arriving in France on June 25, 1917. |
| July 16, 1917 | Ypres | The third battle of Ypres (Passchendaele) began on July 16, 1917. |
| November 07, 1917 | Bolshevik Revolution | The Bolshevik Revolution in Russia resulted in a Communist government. |
| December 07, 1917 | U.S. Declaration of war on Austria-Hungary | The U.S. declared war on Austria-Hungary on December 7, 1917. |
| March 03, 1918 | Russian Peace Negotiations | Soviet Russia concluded separate peace negotiations with their enemies. |
| May 1918 | U-Boats in U.S. waters | U-boats appeared in U.S. waters for the first time in may of 1918. |
| November 09, 1918 | Abdication | Kaiser Wilhelm II abdicated the throne on November 9, 1918. |
| November 11, 1918 | Armistice | The armistice was concluded, and fighting stopped at 11 am on November 11, 1918. |
| June 28, 1919 | Treaty of Versailles | The Treaty of Versailles was signed on June 28, 1919. |
