The Spanish capital aims to reduce heat and improve air quality across the city by encircling itself with a wall of green.
UC San Francisco researchers have developed a "speech neuroprosthesis" that allows a man with severe paralysis to communicate in sentences.
Teens on the island of Islesboro in the US state of Maine display altruism and put the needs of their small community beyond themselves.
A lab in the United States has developed a system that filters wastewater while creating electricity.
Tire manufacturers in Europe are turning to old Soviet methods of rubber cultivation, using what is commonly known as a pesky weed, dandelions, to find more environmentally friendly materials.