9. The whole city is built on an advanced energy grid which monitors the output of every single switch and appliance.
The wind tunnel above (center) is fitted with LED lights designed to glow blue when residents are within their goal of using 50% less energy than a comparable settlement, and red when they are above their goal.
- U.S. Republican presidential candidates will debate Saturday at 9 p.m. ET on CBS for the first time since Donald Trump's win in New Hampshire.
- Bitterly cold temperatures and arctic winds began freezing large swathes of the U.S. Northeast on Saturday.
- And how well do you know what happened in the news this week? Take our quiz.