Thousands will gather Saturday on the shores of the Cuyahoga River to celebrate a transformation. Fifty years ago today, the Cuyahoga was so polluted that it caught fire, due to a combination of debris and chemicals in the water – and it had actually happened many times before. But this time, it galvanized the nation and helped launch the environmental movement which cleaned up the Cuyahoga and countless other waterways across America. New “CBS This Morning Saturday” co-host Jeff Glor reports. Source