The southernmost of the New World or Western Hemisphere continents, with three-fourths of it lying within the tropics. South America is approximately 4500 mi (7200 km) long and at its greatest width 3000 mi (4800 km). Its area is estimated to be about 7,000,000 mi² (18,000,000 km²). South America has many unique physical features, such as the Earth's longest north-south mountain range (the Andes), highest waterfall (Angel Falls), highest navigable fresh-water lake (Lake Titicaca), and largest expanse of tropical rainforest (Amazonia). The western side of the continent has a deep subduction trench offshore, whereas the eastern continental shelf is more gently sloping and relatively shallow.