423,000 people live in Flevoland, a province of the Netherlands. Before 1957, the entire area did not exist.
Remember the (probably apocryphal, or at least exaggerated) history of the French cavalry attacking a fleet of ice-bound ships off the coast of the Netherlands? The shallow bay that was the scene of that improbable battle – the Zuiderzee – is today much smaller than it was in the 18th century. In fact, much of it is now a province of the Netherlands.
How did this happen? Well, the Dutch are big fans of reclaiming land, and Flevoland is their masterwork. In the mid-20th century engineers erected a dam across the mouth of the Zuiderzee (the Afsluitdijk) and then encircled the bay with a series of dikes. Large pumps emptied out the water, and all of a sudden the bottom of the bay became habitable land.
The eastern part of the bay was reclaimed in this way in 1957; the southern part was sealed off in 1967. To allay the risks of flooding a couple of lakes separate Flevoland from the surrounding areas. This technically makes the province an artificial island, easily the largest such island in the world. The second-largest, Kansai International Airport in Japan, is barely one ninth the size.
Flevoland has a ripping great anthem, by the way. It begins, boldly,
Waar wij steden doen verrijzen
op de bodem van de zee,
Where we build up cities
at the bottom of the sea,
I learned about Flevoland while playing the excellent board game Pandemic: Rising Tide. If you’re on the lookout for a board game about the history of Dutch hydrological infrastructure engineering, by the way, I strongly recommend it.