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The digital cloud became a household word in 2011.You can now store and share things via the Internet in ways you never could before. But what does the cloud look like, and where can we find it?

The section of the cloud we visited has a lot of concrete and security.

Behind a ballistics-grade door, data center owner David Sabey ushers us into a spotless Seattle-area facility the size of nine football fields. It's crammed full of racks upon racks of powerful servers, sophisticated computers that serve up information. There are lots of blinking lights and wires everywhere.

Hurricanes topple plenty of trees, but when you think about it, the more amazing thing is that many trees can stand up to these 100-mile-per-hour winds.

Now a French scientist has come up with an explanation for the resilience of trees. And astonishingly, the answer was first described by Leonardo da Vinci 500 years ago.

Leonardo noticed that when trees branch, smaller branches have a precise, mathematical relationship to the branch from which they sprang. Many people have verified Leonardo's rule, as it's known, but no one had a good explanation for it.

In 2011, Novak Djokovic had just about the best year a male tennis player has ever had, including wins at three of the four Grand Slam tournaments.

"This is the athlete of the year," says Jon Wertheim of Sports Illustrated. "This is a brutal, brutal sport. This guy is playing on six continents, every surface....This is one of the all time great years in open tennis history."

This year, Djokovic also kept to a gluten-free diet. Must have been particularly difficult since his family's business is a pizza parlor.