The industrial areas in the Copenhagen suburbs are next in line for urban development. A new light rail is planned to interconnect 20 development zones with a total area of 11 Km2, the size of the entire inner city. We are proposing to turn the light rail line into a spine of dense urbanity with a series of peaks at the stations. By combing the rail with strategies for energy exchange, waste management, water treatment and electric car stations, the infrastructure could become the base for a new sustainable ring of development around Copenhagen, and an artery of true urbanity pumping life into the heart of the suburbs. At certain points the rail becomes a building itself almost like a Roman aqueduct passing through the suburbs, at other points it forms small pockets of urbanity around the stations. We propose to upgrade the planned light rail by extending it to form a regional ring around Oresund connecting similar development areas, and creating a new 50 year development perspective for a cross border region between Sweden and Denmark. Where the Finger Plan from 1947 was about connectivity from suburb to center the Loop City is linking a string of highly differentiated urban nodes, universities and working spaces in a center-less metropolitan region around a blue void. This ring, comparable in size to the San Francisco Bay area, has enough development areas to contain the growth of the region the next 50 years, and could become a model for a both sustainable, dense and super recreational development of the region. To see the LOOP CITY video go to: http://vimeo.com/14672002