4. Student Housing Project Keetwonen, Amsterdam
Here, containers have been used to create 1,000 dorm units for Dutch students, making it the biggest container city in the world. It was launched by Tempo Housing in 2006. Not only does it look hip and provides all the amenities a student could ask for, it also has a rooftop used for rainwater drainage, heat dispersal and insulation of the units below. The award-winning project has received a lot of international attention and is so successful that its planned relocation after 5 years has been postponed until 2016.