World War I combat operations ended with an armistice on Nov. 11, 1918. The war officially ended with the signing of the Treaty of Versailles on June 28, 1919, but Nov. 11 is remembered and celebrated as the end of the war.
Beginning in 1919, Nov. 11 was observed as Armistice Day. Inspired by the poem "In Flanders Field," persons in the United Kingdom observe the day by placing one red poppy for each fallen soldier on the grounds of the Tower of London. After World War II, the United Kingdom renamed its holiday Remembrance Day. The United States renamed it Veterans Day to commemorate the service of all veterans and not just the dead or those of World War I.