The Groothoofdspoort is the only remaining city gate of medieval Dordrecht, set at the apex of the old town where the Merwede, the Oude Maas and the Noord all flow together. The original gate dates from the 14th century; the elegant cupola and the river-facing decoration are later additions from the 17th. From the gate you step straight out onto a stone quay with cafe tables and one of the best free spectacles in the Netherlands: hundreds of barges, container ships and small boats threading through what is one of the busiest inland-water junctions in Europe.
The neighbourhood inside the gate is the most photogenic in town — narrow cobbled streets, tall narrow houses and small canals. The cafe directly on the quay, Groothoofd, is a useful waypoint for a beer in the sun. Spend a quiet half hour watching the river traffic from the bench by the water.