Photo of the Week: Adelie Penguins Take the Plunge

A mongoose is lightning fast and has razor-sharp teeth. A black mamba can kill 15 grown men with just one bite. Which of these two mortal enemies will win?

A Mongoose and Black Mamba Fight to Death (2:33)

Thousands of massive stone monuments, known as Moai, preside over Easter Island. The way they were carved, using only stone tools, seems unfathomable.

How Were Easter Island's Gigantic Statues Actually Carved? (4:11)

Why saying cheese just didnt happen in the early days of photography.

Ask Smithsonian: Why Don’t People Smile in Old Photographs? (1:12)

In 1992, Christopher McCandless set off to test if he could survive alone in the wilds of Alaska. It didn't go as planned.

What Happened to Chris McCandless? (3:38)