Wikipedia
Flevopolder
The Flevopolder is a polder, or region of reclaimed land, in Flevoland, Netherlands. The eastern part was drained in 1955 and the southern part in 1968.
Unlike other major polders such as Noordoostpolder and the Wieringermeer, the Flevopolder is completely surrounded by bordering lakes, the Veluwemeer, Ketelmeer, and Gooimeer. Therefore, it can be considered as a large island; it is the largest artificial island reclaimed on water in the world.
The name refers to the ancient lake Flevo.
The Flevopolder, together with the Noordoostpolder forms the province of the Flevoland, the most recently created province of the Netherlands.