Buildings are responsible for roughly half of the world's total greenhouse gas emissions. A group of architects would like to change that -- to make buildings that use no fossil fuels by the year 2030. The World's Jason Margolis has our story.
Today's Geo Quiz takes us to the Brazilian state of Minas Gerais. Its capital city, and the answer to the quiz, is Belo Horizonte. Damian Francis Wagner recently travelled there and sent an audio ?postcard?.