How much of the Earth do you think has been explored? Sure, humans have trekked the continents and we have satellite maps of the globe, but what about the 70 percent of the planet that's covered with ocean?

Oceanographer David Gallo said today at the Aspen Ideas Festival that perhaps only five percent of the world's oceans have been seen by humans.

Why does that matter? After all, the bottom of the ocean may not seem like the most interesting place in the world. But Gallo argued that all kinds of discoveries might be made in the depths. Like what?

How about this incredibly crowd-pleasing octopus, which has a skill for camouflage that borders on magical. The video was captured by one of Gallo's colleagues at Woods Hole Oceanographic Institution, Roger Hanlon, and you really must see it to believe it. Hanlon has showed the video a few times and some Internet denizen took the pains to slow down and reverse the footage.

What makes the camouflaging so remarkable is that the octopus matches not just the color and pattern of the algae on which it's hiding but the texture, too. In fact, the octopus-camouflage system is fantastically complicated, as you can see in the chart below, which I snipped from a 1980 paper that Hanlon co-authored. There are two dozen ways that the octopus can change its appearance to match its environment.