Fodor's Expert Review Christiansholm Festning
This circular fortress with 16-foot-thick walls, on a promontory opposite Festningsgata, was completed in 1672. Its role has been much more decorative than defensive; it was used once, in 1807, during the Napoleonic Wars, to defend the city against British invasion. You can only visit around the grounds. For the moment the fortress is not available for the public.