Fort McHenry is primarily known for the Battle of Baltimore during the War of 1812, when American troops stopped a British invasion. The battle inspired Francis Scott Key to pen what would become the national anthem, “The Star Spangled Banner” – originally entitled “Defense of Fort McHenry”. During the Civil War, the fort served as a military prison. Another interesting fact: When a new flag is designed for use by the United States, it is first flown over Fort McHenry. This spectacular embodiment of the spirit of America is open most days for a visit and is a must-see for history fans.