The indisputable heft China carries these days as the world's second largest economy means that its every move is closely watched by world markets for clues on future growth and by global investors hungry for the next big thing. And here is one of those big things, a national strategy and a vision for China's future: the Yangtze River Economic Belt. How big is this new regional economy? And how will it change China's national landscape, both economically and environmentally? Mary helps us take a look.