New York City's transit agency loses millions of dollars each year because of people who don't pay to ride the subway. Photo by Adam Fagen.

After 12 months of operation, London’s bikesharing outfit Barclays Cycle Hire boasts roughly 6 million logged bike trips.Photo by Donald Macleod.

Benches with solar panels in Berlin's Potsdamer Platz light up public spaces and serve as an innovative landmark. Photo by Nathan Bush.

Transmilenio buses ready to meet peak traffic demand, Bogotá, Colombia. Photo by Gerardo Arévalo Tamayo.

Solar panels cover a train tunnel in Antwerp, Belgium, providing enough energy to power 4,000 trains for one year. Photo by Adams K.