At the Molenwal is the bastion De Kat, which was constructed after the Hanseatic period in the seventeenth century. Over the centuries, several windmills stood on this bastion. One of the mills that stood there was called De Kat, and that is how the bastion got its name. The bastion is therefore also known as the Molenbolwerk. The site gives a good impression of how the city defences of Zaltbommel were further developed after the Hanseatic period.