31. The Great Lakes on ice

The Great Lakes cover a whopping 94,600 square miles and they make up the world’s largest freshwater system. That’s because all five of them are connected by rivers and lakes between them. And of course, satellites allow researchers to see all of the activity going on at the Great Lakes. This image – shot in January 2015 – revealed that nearly 30 percent of them were covered by ice in the midst of winter.