D.F. Wouda Steam Pumping Station, Gemaalweg 6, Lemmer. Designed by D.F. Wouda, this is the largest steam-powered pumping station in the world that is still in operation, although due to developments in pumping stations and land reclamation it nowadays only works one week a year. It dates from 1920, and has been pumping away excess water in Friesland ever since. It can pump 4,000 cubic metres of water per minute at full power. It is just outside of Lemmer and a UNESCO World Heritage Site since 1998.