Christmas is over for the year. Wrapped presents have transformed into shreds of paper, and we're already finalizing New Year's Eve plans. But do you need some more holiday closure? Then watch this pine tree explode, and you should be all set.
Chinese artist Cai Guo-Qiang regularly does explosive events like this. However you want to interpret their meaning, they're quite a spectacle. Here he set up three separate explosions on the National Mall, blowing up 2,000 black smoke drops attached to the 40-foot tree.
See you in 364 days, Christmas.
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.