Greenpeace activists dangle under a massive banner on an iconic bridge in downtown Pittsburgh with a message to Group of 20 leaders gathering for the September 24 summit in Pittsburgh. The banner, nearly 80-feet by 30-feet in size, takes the form of a stylized road sign warning of the political maneuvering and delay that have put a international climate treaty in jeopardy as the world enters the final stretch on the road to Copenhagen.