Finland is a country of thousands of lakes and islands; 187,888 lakes (larger than 500 m²) and 179,584 islands to be precise. One of these lakes, Saimaa, is the fifth largest in Europe. The Finnish landscape is mostly flat with few hills and its highest point, the Halti at 1,324 metres, is found in the extreme north of Lapland at the border between Finland and Norway. The landscape is covered mostly (seventy-five percent of land area) by coniferous taiga forests and fens, with little arable land. The most common type of rock is granite. It is a ubiquitous part of the scenery, visible wherever there is no soil cover. Moraine or till is the most common type of soil, covered by a thin layer of humus of biological origin. The greater part of the islands are found in southwest in the Archipelago Sea, part of the archipelago of the Åland Islands, and along the southern coast in the Gulf of Finland.