A Danish policeman stands next to an art installation located near the exit of the Bella Center in Copenhagen December 6, 2009. Thousands of environmentalists and politicians will gather here for the United Nations Climate Change Conference 2009 which opens on December 7 and runs until December 18. The biggest U.N. climate talks in history are aimed at working out a new pact to curb global warming, replacing the 1997 Kyoto Protocol.[Xinhua]