Stanford Kay's infographic is not only shaped like a footprint, but tells what kind of carbon footprint countries around the world are leaving. Click the image below to see who is using the most energy.

Potholes are the worst. And, while you're waiting and waiting for the road crew to fill them, why not throw some colorful yarn at the problem? That's what Juliana Santacruz Herrera did at least. To temporarily ease the annoyance for bicyclists, drivers and distracted pedestrians, Juliana grabbed some brightly colored yarn and hit the streets — what is left is a fun, short-term way to make potholes disappear.

Roll clouds may look a lot like a wonky sideways tornado, but don't worry…they aren't dangerous. They result from downdrafts during thunderstorms where clouds break away from each other and create this cool "rolling" effect. Check out the gallery below for more shots of this cloud as it passes over Toronto.

Residents of Copenhagen, be on the lookout for the Sperm Bullitt. This little doozy is part of a green initiative by the Nordisk Cryobank (European Sperm Bank) to avoid using other, less efficient means of transportation. That's right, this bike actually carries sperm samples to Copenhagen fertility clinics. Happy Earth Day to all!