The continent of South America makes up some 12% of the worlds land surface and offers a wide range in both climatic and geographic regions. The lowland areas to the north are dominated by the vast Amazon basin, drained by the Amazon River the second longest in the world. Covering an area of some six million sq. miles much of the Amazon basin is covered by Equatorial Rain Forest, an ecosystem that houses more species of flora and fauna than any other single region of the world. Along the western side of the continent and running almost its complete length is the Andean Range of mountains containing many of the highest peaks in the world.