Beemster polder reclaimed land

dike with a row of willow trees and grazing sheep in beemster polder

Windmills were invented that could pump up water and this was a breakthrough in the battle against flooding. First a dike was built around the lake, the water was pumped out en the land cultivated.
From the 13th century, the Beemster was an inland sea and connected to the Zuiderzee.
In 1607 a number of Amsterdam merchants were given a permit to drain the lake.
In 1612 the work was finished with the 43 windmills.
The new land was divided into rectangular lots of 934 by x 934 meters, among the investors.
The soil was very fertile and the merchants and farmers built beautiful country estates.
The first village in the Beemster is Middenbeemster and is the center of the polder.
The Beemster is twice on the UNESCO World Heritage List. Such as the Beemster polder and five bastions (Middenweg, Marken-binnen, Purmerend, Jisperweg and Spijkerboor) as part of the Defence Line of Amsterdam.

https://www.holland.com/global/tourism/destinations/provinces/north-holland/unesco-world-heritage-sites-beemster-and-de-schermer-en.htm