Earth Day is a big deal here at PopSci. It's a time for admiring our incredible planet, and for giving back-- to the Earth, and to our readers (that means you). We've teamed up with the BBC to bring you a gallery of stunning images from the popular Planet Earth series, video clips (so you can appreciate the full affect), and our most extravagant giveaway yet.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.