The world's oldest active volcano may be Mount Etna — with records of eruptions going back 2,700 years.

The Dead Sea is one of the saltiest bodies of water on Earth.

Fact #266 · Human Body

Border collies can learn hundreds of word-object associations.

Fact #1303 · Human Body

Some insects have compound eyes made of many lenses.

Fact #513 · Human Body

The gulper eel has a large mouth that allows it to swallow prey bigger than its body.

Fact #1386 · Human Body

Some animals can regenerate entire body parts.

Fact #1775 · Human Body

Cats have a reflective layer in their eyes that improves night vision.

Fact #1367 · Human Body

The Earth's inner core is solid despite extreme heat.

Fact #217 · Human Body

The vaccination syringe improved medical delivery methods.

Fact #1576 · Human Body