Paris-based architect Vincent Callebaut wants his buildings to be more than your average tower block. His vision is ambitious: create an energy-saving, carbon-absorbing civilization to fight global warming. "I want to give hope for a better tomorrow," he says. One of his eco-friendly ideas is taking root right now in Taipei, Taiwan's capital city. When Tao Zhu Yin Yuan — meaning "The Retreat of Tao Zhu" — is completed later this year, the residential complex will be covered in 23,000 trees and shrubs.