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A major downtown freeway was demolished in Seoul, Korea, to restore the ancient Cheonggyecheon stream.

Public transportation in Portland, Ore., includes train, streetcar, bus and aerial tram.

Amyris Biotechnologies' new synthetic jet fuels and Hybrid Air Vehicles' second generation of dirigible airship.

A plan to alleviate congestion in London asks drivers to pay for access to public roads and parking spaces.

Paris' bike initiative encourages residents to use bikes and public transportation rather than rely on cars.

Investing in local food systems may be detrimental to the environment.