Gemeenlandshuis Zwanenburg

The Hoogheemraadschap van Rijnland built this building as a meeting hall to use for water management of the IJ and the Haarlem Lake in 1645.

This granting of privileges by Count William II of Holland was the subject of a painting by Caesar van Everdingen that was painted as decoration for the meeting hall in Halfweg, and which hangs today in the Gemeenlandshuis van Rijnland, the meeting hall purchased in 1578 on the Breestraat in Leiden.

The duties of the dike warden changed over time and Zwanenburg evolved into a weather station.

The Zwanenburg resident Jan Noppen (1706–1734) and his friend and Spaarndam water board colleague Nicolaas Kruik were inspired by the British Royal Society to measure the temperature, air pressure, humidity, and rainfall 3 times daily.

For example, when it was too dangerous to run the mill, it was considered "molenwind 13", which today is "windkracht 8" or gale force on the Beaufort scale.