Along the northern shore, the Wadden Sea creates a totally distinct Dutch seascape: a vast, shallow tidal realm of mudflats, sandbars, and salt marshes. Shared by the Netherlands, Germany, and Denmark, it is …

Much of the Netherlands would not exist without polders—large expanses of land recovered from lakes, marshes, and the sea by enclosing them with dikes and pumping out the water. Engineers estimate that …