Unnamed bank just south of Madagascar was once a large tropical island
Island of the Batavians in the Netherlands. It used to be an island in the Rhine delta between the rivers Waal and Rhine . The island disappeared due to silting up of the Rhine, floods and the building of dikes, canals and dams for irrigation. Cities in the area that used to be the island are (most of) Rotterdam , The Hague , (half of) Leiden , Gouda , Nieuwegein , Tiel , (part of) Arnhem , (part of) Nijmegen .