The only thing left of the 15th century water castle of Diegem is the gate tower. The engravings from the 17th century show us a castle built in white sandstone from the local quarry. Major restoration where done in 1564. the castle was the home of the Lords of Deigem. The now beautiful restored gate tower became a protected historical monument in 1939 but the tower was neglected and decay set in. The village bought the remains in 1953 and built a new complex with the stones from the ruin where the old castle stood behind the tower. The tower was restored in 1987.