Off the coast of Muiden lies a derelict fort on the island of Pampus. This massive 19th-century bunker was a key member of a ring of 42 fortresses built to defend Amsterdam. Rescued from disrepair by Unesco, it's now a World Heritage Site and is great fun to explore. Ferries to Pampus depart from Muiderslot port on a varying schedule in season. Usually there's at least one morning departure which allows a couple of hours to prowl the fort before a midafternoon return.
