Stephen Hawking is well known for his work in theoretical physics. In honor of his 75th birthday, here are ten fun facts you might not know.

How an orphaned Syrian bear named Wojtek became a Polish army hero.

We call it an epidemic today, but for centuries medical experts encouraged the use of heroin.

The idea that Mary Toft gave birth to rabbits is ridiculous. The fact that most of Britain believed her story is even more astounding.

This is the human body as you've never seen it before.

It was sexism, not a horse -- as one infamous rumor goes -- that brought down the powerful Russian empress known as Catherine the Great.

Fascinating facts about the world's most powerful man.

How a teenager named Jackie Mitchell struck out two of baseball's greats and why her story has historians puzzled.

As the situation grew more and more dire in Vietnam, America's Vietnam War protests grew stronger and stronger.

Turns out dolphins make for far more than good children's movie protagonists.