The Sundarbans, India and Bangladesh

The Sundarbans contain close to 4,000 miles of water and land in the Ganges Delta. They're home to the largest area of mangrove forests in the world. These forests provide a refuge for a number of endangered species, like tigers. Deforestation, pollution, and a strong dependence on fossil fuels are causing sea levels to rise rapidly in the area, which has led to the erosion of precious coastline.