The ocean is a vast, deep, dark place. It has long been a source of mystery and fascination, inspiring epic tales. Early attempts to measure and better understand its depths involved dropping a rope overboard until the end hit bottom, then hauling up the line hand over hand, counting the lengths. The length of rope between a person's hands when outstretched - roughly six feet - was known as a fathom, and the verb 'to fathom', as a result, came to mean to measure the depth of something and ultimately, to comprehend it. After all, once we measure something, we immediately know something about it and can start to understand it.

But can you imagine measuring the entire ocean with lengths of rope, when some parts are nearly seven miles deep? Not only would it be practically impossible, but it's a project that's difficult to even imagine pursuing. You might even say it's unfathomable. The truth is, even with the help of today's satellites, the most sophisticated global maps of the ocean floor are really just guesswork. Satellites can hardly see past the surface of the water, let alone the ocean floor, and so the ocean remains relatively opaque to our eyes, our technology, and for the most part, our understanding.

Given how hard it is to study the ocean, it's important to make the most of what we do know. We believe a key step in understanding is visualization -
this is one of the main reasons we added the oceans to Google Earth. Miles of rope, and the mysterious depths they measure, now fit on a small computer screen. Maps are, of course, just one form of visualization. Sometimes it takes a piece of artwork, something less literal and more symbolic, to make that which might seem overwhelming easier to understand. No matter what form a visualization takes, it offers promise as a starting point for comprehension, which hopefully will lead to more informed choices.

Visualizing the ocean is especially relevant today, the first UN-recognized World Oceans Day. The UN's chosen theme is "Our Oceans, Our Responsibility," which might seem like it ought to read "big oceans, big responsibility." To help get our heads around the watery part of our planet, we've collected a few visualizations of both issues facing the ocean and cutting edge science. Have a look at the problem of plastics in our oceans, find out about where currents might take your trash, the health of the world's fisheries, and what the latest satellite data says about the state of the ocean. If you find yourself wanting more, you'll also see a ticker at the bottom of the page with World Oceans Day news, and a custom search box in the upper right to help you navigate through the rich content on some of our partner sites.

Ready? Go see for yourself.