Architecture in Southern Canal Ring

These impressive sluices (locks) date from 1674 and are still in use to refresh the city's canals. They allow the canals to be flushed with fresh water from lakes north of the city, rather than saltwater from the IJ River, an innovation that made the city more liveable. The locks are shut while fresh water flows in, while the sluices on the western side of the city are left open as the stagnant water is pumped out to sea.