Geography of the European Netherlands European part of 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
European land exploration of Australia discovered—the Darling, Macquarie, Murray and Murrumbidgee rivers—all of which flowed west, a theory was developed of a vast inland sea into which these rivers flowed. Another reason behind the idea of an inland sea was that Matthew Flinders, who had very carefully mapped much of Australia's coast had discovered no great river delta where these rivers should have emerged by had they reached the coast. The Murray-Darling basin actually drains into Lake Alexandrina. Matthew Flinders had noted this on his maps but viewed from the sea does not look like the outfall of a large watershed, but instead as a