This open air library by Karo Architekten is easily the most forward-thinking and Utopian book repository you've ever heard of, especially because it allows local residents to walk up and take books whenever they want.
Originally built by locals on the site of an old warehouse, the open air library began as a community collection of thousands of empty beer cartons. Eventually, however, the building was given a professional retrofit by Karo Architekten in order to turn it into a green and sustainable space with a decidedly altruistic agenda.
The open air library by Karo Architekten allows anyone to walk up to the building and to take as many books as they want -- all without a membership. This, coupled with the building's stage and grassy cafe, helps make it a fantastic addition to the area's residential community that goes above and beyond the call of duty.