Strange and crazy architecture, communities, and cities hold great fascination for us, and the fine folks as io9.com have another amazing post about such things: 10 Weirdest Urban Ecosystems on Earth.
From the sprawling, enviro-friendly and THX-1138-ish former limestone mine now underground office/business complex called "SubTropolis" in Kansas City, MO (super BBQ AND underground complexes, go figure) to the slums of Mumbai and the Garbage City of Egypt (HOW do people live this way?) to the artificial Japanese island Gunkanjima (SOMEONE'S gotta film an end of the world movie there!) to the breathtaking centuries old city of Petra, carved out of the canyon walls in Jordan (yup, as seen in Indiana Jones and the (Next to) Last Crusade).
It's a wild mishmash sampling of humanity's ingenuity, from the insane to the incredible.