Depending on who you ask, somewhere between 300 and 400,000 people descended on upper Manhattan on Sept. 21 to march in solidarity for climate change. It was a lively gathering packed with people from all over the US and the globe, and one that outspoken activist and author Bill McKibben called "the largest political gathering about anything in America in at least a decade." The People's Climate March was a gathering to raise awareness about climate change ahead of the United Nations' Climate Summit, where Secretary-General Ban Ki Moon has invited world leaders to take action on curbing global warming.