Lemon-colored Fort Christiansvaern is a well-preserved stronghold on the waterfront overlooking a northern edge of St. Croix. The building is located on the grounds of the Christiansted National Historic Site, and previous visitors say the best way to experience Christiansvaern is with a walking or driving tour. Exploring the fort's exterior and perimeter should only take 30 minutes tops, but as long as you're here, you should also stop by the Danish Custom House, the Scale House and the Danish West India & Guinea Company Warehouse, where former St. Croix resident and founding father Alexander Hamilton worked as a young man. One TripAdvisor user conisders it a must-see: "The fort is very worth a visit when in Christiansted. It provides a concentrated insight to the history of the island — its settlement, slavery, emancipation, and eventual turnover to [the] U.S."

You can tour the fort Monday through Friday 8 a.m. to 4:45 p.m. and 9 a.m. to 4:45 p.m. Saturday and Sunday for a $3 entry fee. For more information, check out Fort Christiansted's website.