Today is Rememberance/Veterans/Armistice Day
November 11 is 91st anniversary of World War One ending. Many countries around the world who participated in that war chose the anniversary of it's ending to mark the historical significance of the war. Some, like the United States, called it Armistice Day, while others named it Rememberance Day.
Shortly after the end of World War 2 the United States renamed their November 11 rememberance to Veterans Day, to honor all their veterans who had fought in previous wars. Other allies, such as Canada and Britain, kept the Rememberance Day title but incorporated the veterans of WW2 into their memorials.
Anyway, when you're out today and you see a veteran, don't just ignore him. Thank him.