In Earth's most extreme habitats, conditions are tough. But no matter how challenging these deserts, rainforests, mountains, caves, ocean depths or cities are, there are plants and animals that have found ways to survive in them through unique adaptations. Called extremophiles, these are the toughes...

In Earth's most extreme habitats, conditions are tough. But no matter how challenging these deserts, rainforests, mountains, caves, ocean depths or cities are, there are plants and animals that have found ways to survive in them through unique adaptations. Called extremophiles, these are the toughest living things on the planet!