Donderstad Castle is an old castle located in Donderstad, Brunant. Donderstad Castle was built from 1420-1480, when there were still fears that the Venetians could invade and reclaim the islands. But, the lack of funds in the government led to its construction being delayed and it was only completed 60 years after the start. Master builder Maximilian Sechter was in charge of much of its construction. Donderstad Castle still is an important military base used today, but it also has a small museum. It is a National Monument since 1980 and has its own museum, gift shop and restaurant.