This is the Egypt familiar to most people.Cairo has been "going green" long 
before it became fashionable. That's why National Geographic Emerging Explorer Thomas Taha Culhane's 
program has been so special. He's been helping lower-income Egyptians
build solar-powered water heaters--partly out of recycled trash--and 
putting them on their rooftops. Thomas Culhane: People will come to this community, and they'll look on the rooftops and
they'll say why is there so much trash on the roofs, but if you talk to the 
homeowners they'll say, "What trash?It's an easy thing to do. Culhane hopes the water heater project will lead to other innovations using 
recycled materials.Many Egyptians use the space on rooftops for water tanks, satellite dishes, 
and even livestock.The garbage piled everywhere is considered valuable 
because it's often recycled and reused.Once they accept that, solar is 
a no-brainer here.Cairo is a big, busy city.But there's 
a whole other world up here, high on the city's rooftops.And what we have to do is get them to be as aware of the need to just dust 
these as they are dusting their kitchen table.As the saying goes, one man's garbage is another man's 
treasure