Behold the toughest animal on Earth, that survives being boiled, frozen, dried, exposed to radiation and can live in space.

It's often said cockroaches could withstand a nuclear explosion.

But another creature, dubbed 'nature's greatest survivor,' is even more invincible, and you've probably never even heard of it.

Tardigrades, also known as water bears, are some of the most fascinating animals in world because they can live happily in the most extreme conditions.

While not the most attractive creatures, the small, segmented animals come in many forms - there are more than 900 species of them - and they're found everywhere in the world, from the highest mountains to the deepest oceans.

Boil the 1mm creatures, freeze them, dry them, expose them to radiation and they're so resilient they'll still be alive 200 years later.

Water bears can hack temperatures as low as -457 degrees, heat as high as 357 degrees, and 5,700 grays of radiation, when 10-20 grays would kill humans and most other animals.

The animals can also live for a decade without water and even survive in space(...)