Each week our friends at Inhabitat recap the week's most interesting green developments and clean tech news for us -- it's the Week in Green.

Inhabitat's Week in Green TKTKTK

This week held some truly unexpected breakthroughs as scientists in China figured out a way to create brain cells from human urine, and researchers at Rice University and CUNY developed batteries that are fueled by the dye from madder roots. Over in Germany, researchers unveiled a technique that harnesses the power of lightning to break up concrete into usable building materials and scientists at MIT built a tiny, caterpillar-size robot that can transform into almost any shape.

We've been hearing a lot of bad news about the environment such as climate change throwing natural systems out of balance, but things could be looking up slightly. Last week at the Doha climate conference, 200 nations agreed to extend the Kyoto Protocol to 2020 and back in the US, a report showed that Americans installed a record-breaking 3.2 gigawatts of rooftop photovoltaic panels in 2012. And if all else fails, Harvard professor David Keith, proposes geo-engineering as a way to combat global warming with his plan to refreeze the Arctic.

In green architecture news, a New York architect has come up with a proposal to blanket the unsightly West Side Highway with air-cleaning ivy and dramatic waterfalls, while in Sarajevo, we saw the opening of the winding Festine Lente pedestrian bridge. In one of the most exciting design stories of the week, MAD Architects' curvaceous Absolute Towers popped up in Canada, and MVRDV's pixelated DNB NOR Bank Headquarters also came to fruition in Oslo.

Strides were made in the world of green transportation this week when the Solar Impulse team announced that they will attempt to fly their sun-powered plane from San Francisco to New York, which would be the first solar-powered, cross-country flight in US history. Meanwhile, a team of Yamaha motorcycle designers will attempt to set a world record of their own when they fly their pedal-powered airplane over 75 miles of the Pacific Ocean. We also profiled the ELF, a three-wheeled solar-electric-assist velomobile designed by Organic Transit.

In other green tech and design news, Hitachi unveiled an impressive new wireless controlled robot to help with the Fukushima Daiichi cleanup and London-based designers Martin Riddiford and Jim Reeves developed the GravityLight, an amazing low-energy, battery-free light that works by harnessing the power of weight and gravity. Lastly, the week saw the unveiling of the world's first fiber-optic solar cell, which is thinner than the width of a human hair and could pave the way to creating energy-producing clothes.