The old castle of Schwanenburg (formerly the residence of the dukes of Cleves), has a massive tower (Schwanenturm) 180 ft.
To the south and west of the city a large district is laid out as a park, where there is a statue to the memory of John Maurice of Nassau-Siegen (1604-1679), who governed Cleves from 1650 to 1679, and in the western part there are mineral wells with a pump room and bathing establishment.
Owing to the beautiful woods which surround it and its medicinal waters Cleves has become a favourite summer resort.
The town was the seat of the counts of Cleves as early as the 11th century, but it did not receive municipal rights until 1242.
The death without direct heirs of Duke John William in 1609 led to serious complications in which almost all the states of Europe were concerned; however, by the treaty of Xanten in 1614, Cleves passed to the elector of Brandenburg, being afterwards incorporated with the electorate by the great elector, Frederick William.