‘Her sides are made of iron!’ cried a crewman upon watching a shot bounce off the thick oak hull of the USS Constitution during the War of 1812. This bit of irony earned the legendary ship its nickname. Indeed, it has never gone down in a battle. The USS Constitution remains the oldest commissioned US Navy ship, dating from 1797, and it is normally taken out onto Boston Harbor every July 4 in order to maintain its commissioned status.

　　Make sure you bring a photo ID to go aboard. You'll learn lots, such as how the captain’s son died on the ship's maiden voyage (an inauspicious start).