Until now, there was no universal, comprehensive methodology for cities around the world to measure their emissions. One of the tool's creators explains its power in the fight against climate change.

Private companies are paying the city $500 million to transform old pay phones into high-speed Internet hotspots. Is it a plan other cities can copy?

Once wide open and famous for sprawl, the Texas city is becoming increasingly crowded and expensive.

Cities are trying to curb people’s driving habits, but most Americans aren’t ready to give up their cars.

Each are crucial for states and localities to address this year.