The fortress in Muiden, known as Muizenfort is part of the Stelling van Amsterdam, the UNESCO World Heritage site that consists of a set of forts around the city of Amsterdam. The defence line was 135 km long ring of fortifications around Amsterdam, consisting of 42 forts located between 10 to 15 kilometers the centre, and lowlands that can easily be flooded in time of war. The flooding was designed to give a depth of about 30 cm, insufficient for boats to traverse. Any buildings within 1 km of the line had to be made of wood, so that they could be burnt and the obstruction removed. The Stelling van Amsterdam was constructed between 1880 and 1920. The invention of the aeroplane and tankmade the forts obsolete almost as soon as they were finished.
These days, the Muiden fort is used for offices as well as a small museum, the Muider Muizenfort Museum (MMM).
References:The Château du Lude is one of the many great châteaux of the Loire Valley in France. Le Lude is the most northerly château of the Loire Valley and one of the last important historic castles in France, still inhabited by the same family for the last 260 years. The château is testimony to four centuries of French architecture, as a stronghold transformed into an elegant house during the Renaissance and the 18th century. The monument is located in the valley of Le Loir. Its gardens have evolved throughout the centuries.