This 32-cent definitive stamp honors the 200th birthday of America's 11th President, James K. Polk. Polk was the first man to be elected President under the age of 50 - and also the first dark-horse candidate to win the office. Many important events occurred in the United States under Polk's leadership: America's western boundaries were pushed all the way to the Pacific Ocean, The Canadian and Mexican borders were defined, the U.S. Naval Academy and the Smithsonian Institution were established, the first known baseball game was played, and the first U.S. postage stamp was issued.