Happy Veterans Day!
During WWI, in 1918, an armistice was observed at the 11th hour of the 11th day of the 11th month. From then on November 11th marked Armistice Day, a day to celebrate the veterans of WWI. Later in 1954, President Eisenhower changed it to Veterans Day, to honor veterans of other wars as well. This is not only an American holiday, but is celebrated in many countries, often called “Remembrance Day.”
There are a few surviving WWI veterans left (10, according to this article), and there are also many survivors of the wars since who have given a great deal for the countries that they serve. For more information, check out the Department of Veterans Affairs’ website on the subject. It includes history, FAQ, and even a poster gallery spanning the last 30 years.