Amazon Rainforest, Brazil

The Amazon is the largest rainforest on the planet, covering 3.4 million square miles over nine nations and home to 20 percent of all plant and animal species in the world. Over the past 30 years, however, nearly 373,000 square miles of the rainforest have been felled in Brazil alone. At that rate, more than 30 percent of the forest could be gone by mid century.