(Flevoland): Flevoland is the fastest growing providence in the Netherlands.
(Polder): Polders are typically found in the Netherlands, they are a low-lying land that has become apart of the sea.
(Sea level): Sea level is the shore line, anything above this is above sea level and anything below the sea is below sea level.
(Reclaim): The sea has reclaimed the land that was once a beautiful sandy beach area.
I hope this helps you.