Built in 1280 by Count Floris V, son of Willem II, the exceptionally preserved moated fortress Muiderslot is equipped with round towers, a French innovation. The count was a champion of the poor and a French sympathiser, two factors that inevitably spelt trouble; Floris was imprisoned in 1296 and murdered while trying to flee. Today it's the Netherlands' most visited castle. The interior can be seen only on 30-minute guided tours. The I Amsterdam and Museum cards allow free admission.
In the 17th century, historian PC Hooft entertained some of the century's greatest writers, artists and scientists here, a group famously known as the Muiderkring (Muiden Circle). You'll be taken around the castle on the 'Golden Age' tour, seeing precious furnishings, weapons and Gobelin hangings designed to re-create Hooft's era.