This paper focuses on two places with the same, telling name: Waterland. On the banks of the river Suriname, on the northern seaboard of South America, Waterland was a sugar plantation. On the shores of the Wijkermeer, east of the dunes lining the North Sea coast, Waterland was a country estate. Connecting the histories of these Waterlands shows that plantation and colonisation could also be European phenomena, and that water was essential to them on both sides of the Atlantic. The seasonality of drainage, irrigation, and waterborne transport set the yearly rhythm of life in both Waterlands. In the Low Countries, wetlands were sacrificed to the needs of dairy and arable farming using the same hydraulic techniques which enabled the replacement of the rainforest with sugarcane in the Caribbean. Control of water was key to reducing biodiversity in both cases. Architects, engineers, and surveyors trained in the metropole were not alone in deploying these hydraulic techniques: my research seeks to recover the voices of indigenous communities and enslaved labourers, whose agency has been written out of histories of Suriname and the Low Countries. Ultimately, this paper centres water as a key element of architectural histories. I argue that water was essential to architecture, for building materials were shipped and floated, and architecture was essential to water, which needed to be channeled, dammed, and evacuated.