The Citarum has been called the world's most polluted river. Around five million people live in the river's basin, and most of them rely on its flow for their water supply.
Chernobyl is the town in northern Ukraine home to the Chernobyl disaster of 1986, the worst nuclear power plant accident in history. Once home to more than 14,000 residents, the town remains mostly uninhabited and unsafe today due to extensive radioactive contamination.
Linfen, China
Linfen has more air pollution than any other city in the world. Sitting at the heart of China's coal belt, smog and soot from industrial pollutants and automobiles blacken the air at all hours. It is said that if you hang your laundry here, it will turn black before it dries.
The North Pacific Gyre
An island of trash twice the size of Texas floats in the middle of the Pacific Ocean, circulated by the currents of the North Pacific Gyre. The trash, which is mostly made up of plastic debris, floats as deep as 30 feet below the surface.
Rondônia, Brazil
Rondônia is a state in northwest Brazil which, along with the states of Mato Grosso and Pará, is one of the most deforested regions of the Amazon rain forest. Thousands of acres of forest have been slashed and burned here, mostly to make room for cattle ranching.
Yamuna River, India
The Yamuna is the largest tributary of the Ganges River. Where it flows through Delhi, it's estimated that 58 percent of the city's waste gets dumped straight into the river. Millions of Indians still rely on these murky, sewage-filled waters for washing, waste disposal and drinking water.
La Oroya, Peru
La Oroya is a soot-covered mining town in the Peruvian Andes. Ninety-nine percent of the children who live here have blood levels that exceed acceptable limits for lead poisoning, which can be directly attributed to an American-owned smelter that has been polluting the city since 1922.