CAIRO, EGYPT - December 15: A machine worker builds and repairs the parts used in recycling on December 15, 2014 in Cairo, Egypt. Nestled under the cliff of Mokattam is Manshiyat Naser, or Garbage City. It is a majority christian neighborhood with an economy built on waste collection and recycling. Families divide responsibility from collecting trash, sorting it, processing it, and either selling it to outside factories or processing it into final goods. (Photo by David Degner/Getty Images).