Last week the United Nations issued a report on the need for developing sustainable infrastructure in cities. The results won't come as a surprise to most regular readers of this site but in a broader sense they bear repeating: smarter urban infrastructure brings economic benefits alongside environmental ones. What's most useful about the report, however, was its detailed description of 30 projects from around the world meant as models for others to emulate [PDF].
A number of these case studies focus on innovations that have gained their share of recent attention. Urban gondolas have become a hit in Medellin, the conversion of an urban expressway into a pedestrian park earned awards for Seoul, and concern for the climate in Portland is bigger news when it doesn't exist. But there are several other efforts you may not know about. We've pulled out a few of the most intriguing ones.