Climate activists gather in Marseille, southern France, inside a foutain, holding the number 350, representing what scientists say is the safe upper limit for carbon dioxide in the atmosphere, during a demonstration called by 350.org on October 24, 2009, to kick off the International Day of Climate Action about global warming. Similar stunts actions are planned in some 4,000 locations in more than 170 countries across the globe to mark 50 days until world leaders meet in Copenhagen to thrash out a new climate change treaty.