Fronteras: For several decades mules have delivered mail to the bottom of the Grand Canyon, but now the company that runs the mule train plans to stop the package service. Plans to ship nuclear waste from leaky tanks in the state of Washington to New Mexico are stirring up an old debate about the storage of toxic waste. Also, filmmaker Rodrigo Gudiño tells us about his latest work, which is fueled by his earliest memories of being horrified by religious images.