If you live in a big city, you probably know how dangerous bike messengers can be, suicidally zipping in and out of traffic at high speeds and smacking pedestrians in the head with their bike locks. But in a crowded city, if you want a package delivered as soon as possible, they tend to be the quickest option.
If designer Phillip Hermes has his way, though, your packages might be delivered by scurrying underground robots instead. Via the sewer.
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.