South America: Andes, Amazon and Atacama

The Andes run along South America's west coast: the continent's largest mountain range, home to Mount Aconcagua, the highest peak in the Western Hemisphere, and to Bolivia's Uyuni Salt Flats, the largest salt flat on Earth.

They are a vital source of fresh water for millions, feeding major rivers including the Amazon, the world's largest river by volume (the most water).

They are also rich in wildlife, with thousands of species of mammals, birds, amphibians, reptiles and fish, many found nowhere else. But only about one-fourth of the original plants and animals remain, which makes the Andes a critical conservation hotspot.

The Amazon River flows from the Andes in Peru east to the Atlantic, and its basin, with all its tributaries, supports the Amazon Rainforest: tall, mostly evergreen trees getting very high rainfall.

Almost 400 indigenous communities (peoples who have always lived there) live in that forest and play an important part in protecting it. Today the Amazon is threatened by deforestation and climate change.

One detail shows how connected the planet is: dust travels all the way from the Sahara to the Amazon, carrying phosphorus that the rainforest's plants need. A desert on one continent fertilises a rainforest on another.

Further south lies the Atacama Desert in Chile: one of the driest places on Earth, about 1,000 km long, with temperatures swinging from 40°C by day to 5°C at night.

Its clear night skies make it famous for stargazing, and its Mars-like landscape has been used by NASA to test rovers. It has also become one of the world's fastest-growing dumps for thrown-away clothes, driven by cheap fast fashion (trendy clothes copied quickly and cheaply, often made by low-paid workers): a waste problem the UN has called "an environmental and social emergency".