The autonomous underwater robot known as DepthX has completed its exploration of one of the worlds deepest sinkholes, Mexicos Sistema Zacatón. Diving almost 1,100 feet into this massive, water-filled network of caves, DepthX penetrated far deeper than human divers have ever reached. It brought back samples of water and slime coating the cave walls.
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.