the greenest ever. but many experts dispute that claim, saying the cost to the natural environment has been enormous. cnn s david culver explains. reporter: less than a week to go before the olympic flame once again burns in beijing. but for these, the second games hosted by china, a big commitment to the environment. beijing touting this as the first olympics fueled 100% by renewable energy. cnn visiting one of the mountain ski venues during construction. we could see dozens of wind turbines in the distance. and beyond that solar fields. validation, so it seems, of a greener games blanketed by a white layer of snow. while china wants the world s attention to be on the competition, some are raising concerns with what was lost to make these games possible. the games are happening in three main zones. one within the capital city, beijing. the other two on the outskirts,