Great History
The oldest fort, in the oldest town in America; yet it still is entertaining.
This is a truly imposing structure, and is amazingly well preserved and maintained.
If you simply walk around the fort, you get a great view of the city, the river going by, the bridge of lions, and the structure of the fort itself. You can do all of that for free.
If you pay a little bit you get to go into the fort itself and take a tour of this amazing place, complete with hourly drilling and firing of the cannon by the rangers.
Both the history and the view make this place worth a visit.