U.S. Mint — New Orleans

Three governments claimed this building between 1838 and the end of the Civil War. The United States built it, the State of Louisiana seized it, and the Confederate States of America ran it briefly before the metal ran out. It's the only mint in American history to answer to three sovereignties — and that distinction alone makes the coins carrying the 'O' mint mark among the most sought-after pieces in numismatic collecting. The building produced $307 million in coinage over its working life. When Confederate forces took the mint in 1861, they struck their own silver half-dollars until the bullion was gone. A year later, William Mumford tore down a Union flag flying over the building. General Butler had him hanged outside for it — a public execution that defined the bitterness of federal occupation as clearly as any battlefield. New Orleans was the only North American city that allowed enslaved people to gather in public and play their own music, largely in what is now Louis Armstrong Park. That permission created the conditions for jazz. The building that once minted coin now houses the New Orleans Jazz Museum, which holds one of the finest collections of jazz instruments in the world. That includes Louis Armstrong's first cornet. The museum is open Tuesday through Sunday, 10am to 4:30pm. Admission is charged.