For the first time in history, more than half the population lives in cities. Because of urbanization every year we destroy untold amounts of plants and fertile soil. With this in mind, how can we make cities more sustainable? This program takes a special look at green roof gardening, the expansion of solar panels and thinking 'inside the box' with food container gardening. Big cities leave big trouble for the natural world. The good news is we have the ability to change. There are currently innovative technologies in place that will help combat climate change in big cities.