The country can be split into two areas: the low and flat lands in the west and north, and the higher lands with minor hills in the east and south. The former, including the reclaimed polders and river deltas, make up about half of its surface area and are less than above sea level, much of it actually below sea level. An extensive range of seawalls and coastal dunes protect the Netherlands from the sea, and levees and dikes along the rivers protect against river flooding. The rest of the country is mostly flat; only in the extreme south of the country does the land rise to any significant extent, in the foothills of the Ardennes mountains. This is where Vaalserberg is located, the highest point on the European part of the Netherlands at above sea level. The highest point of the entire country is Mount Scenery (887 metres or 2,910 ft), which is located outside the European part of the Netherlands, on the island of Saba in the Caribbean. The Netherlands is located at mouths of three major European rivers (Rhine, Maas or Meuse, and Scheldt).