Dark tower of dreams: Inside the Walled City of Kowloon

Air Date: Oct 18, 2017 12:00 AM ET

The infamous "Walled City of Kowloon" was once the most populous spot on the planet. With 1.2 million people per square kilometre, it was a gigantic squatter's village. Paul Kennedy speaks with photographer Greg Girard, and urban designer Suenn Ho.