Museum Muiderslot in Gooise Meren

You're standing at Muiden Castle, in Muiden, where the river Vecht flows into what used to be the Zuiderzee. Have a look at this castle. It's a proper moated fortress: square, with a round tower on each corner, a moat and a drawbridge. It's exactly what you picture when you think of a castle, which is why it often turns up in TV series set in the Middle Ages.