The Andes mountains run the entire length of South America. They contain unique ecosystems like the páramo between the forest line and snow line. South America also contains the world's driest desert (the Atacama), the highest commercially navigable lake (Lake Titicaca), and extensive grasslands like the Llanos and Pampas. The longest rivers are the Amazon and Paraná, which flow through rainforests containing tremendous biodiversity and through some of the largest hydroelectric plants. Isolated tepui mountains in Venezuela also host unique wildlife.

1. South American Geography Supplement to National Geographic video

2. South America Fourth largest continent

3. Andes Mountains The Andes run the entire length of South America, from the humid tropics of the Caribbean to the ice fields of Patagonia, the longest north-south mountain range in the world.

4. Paramo A neotropical Andean ecosystem located in the high Andes region, between the upper forest line and the permanent snow line. Typical páramo vegetation around L ake Caricocha, Mojanda, Ecuador. Espeletia (Frailejón) plant in the Venezuelan páramo.

5. Cordillera Oriental Montane forests tamandua Lush forests of this semi-tropical ecoregion carpet the middle-to-high elevations of the northern Andes and surrounding foothills.

6. The Llanos an extensive system of grasslands, seasonally-flooded plains, and forests shared by Venezuela and Colombia. It is located to the north and w est of the Río Orinoco and borders the Amazonia wilderness along its entire southern edge.

7. Llanos cattle

8. Altiplano where the Andes are at their widest

9. Lake Titicaca the highest commercially navigable lake in the world, at 12,507 feet above sea level.

10. The Ra Expeditions (above) Contemporary reed boats and boatmen on Lake Chad, Chad, Africa. (below) Aymara reed boat builders at Lake Titicaca, Bolivia, South America. Is it possible that African sailors had visited the Americas thousands of years before Columbus?

11. "Ra II", the reed ship Thor Heyerdahl used for his expedition across the Atlantic, from the coast of Africa southwest toward South America, 1969.

12. Atacama world’s driest desert It is virtually sterile of plant or animal life.

13. Peru Current Dry climatic conditions are a result of this current, also known as the Humboldt Current. This system contains cold, low salinity waters that flow in the direction of the Equator and can extend 1,000 kilometers offshore.

14. Patagonia Chilean steppes

15. Patagonia ice floes

16. Lago, Argentina

17. Patagonia A lake in Neuquén, Argentine portion of Patagonia

18. Pampas Fertile South American lowlands, they cover more than 750,000 km², mostly in Argentina.

19. Pampas These fertile plains are Argentina's bread-basket.

20. Loess These fine, wind-borne particles result in tremendous soil fertility.

21. The Amazon Basin

22. North Brazil The Amazon drains an area equivalent to more than two thirds of the continental United States. It pours into the Atlantic Ocean about one-fifth of the freshwater that flows into all the world's oceans, a volume so gigantic that it alters ocean salt levels 200 miles from its mouth.

23. Amazon River The second-longest river in the world, the Amazon is 3,900 miles long flowing across North Brazil before entering the Atlantic Ocean near Belem. It carries more water than any other river in the world. The source is the Andes Mountains. A school of sharp-teethed piranha can devour a cow in minutes

24. Rio Negro Confluence with Rio Solimões

25. Rain forest Tropical rain forests are mainly the product of climatic interactions, particularly temperature and rainfall. In general, tropical rain forests occur where a mean monthly temperature of between 20 and 28 degrees C is combined with an annual rainfall of between 1.5 and 10m, evenly distributed throughout the year.

26. Biodiversity One square kilometre of Amazon rainforest can contain about 90,790 tons of living plants. This accounts for about a third of all known living plants and animal species in the world.

27. Angel Falls The highest waterfall in the world, at 807 metres, is Angel Falls in Canaima National Park in southwest Venezuela. It is named after an American pilot and explorer, Jimmy Angel, who spotted the falls from an airplane in 1935 and later crash- landed nearby.

28. The Itaipu hydroelectric power plant on the Parana River is a joint development project with Brazil and Paraguay. With 18 units of 700 megawatts each, it is the largest hydroelectric plant currently in operation in the world

29. tepuis The plateau of Roraimatepui. The peculiar rock formation is caused by erosion. This 2 billion year old Pre-Cambrian geological formation is possibly the oldest on the planet. It hosts the impressive and mysterious table-like mountains called tepuis. Guinea Highlands

30. Tepuis the imposing rock walls have led to the evolution of a different world of animal and plants, isolated from the forest below.