Photo: Schwerdf, CC BY 4.0
Historic site
Castillo de San Marcos
The oldest masonry fort in the continental U.S., guarding St. Augustine's bay since the 1600s.
- 1-2 hrs
- Daily 9 am-5 pm last entry; closed Thanksgiving and Christmas
- Adult $15 for 7 days, 15 and under free
- Confirm fees and hours before you go
Heads-up: Crowded on weekends and holidays. Little shade on the walls.