At Tokyo Station, one of Japan's busiest subway terminals, shaken commuters grabbed one another to stay steady as the ground shook.

CNN: Widespread destruction from Japan earthquake, tsunamis

In 2007, China launched the first satellite of its second-generation system, called Beidou-2, which is thought to use cheaper terminals and, unlike its predecessor, doesn't require a ground station.

WSJ: Beijing Launches GPS Rival

To date, 64 European airports have signed up to the Airport Carbon Accreditation Scheme, a voluntary initiative launched in 2009 that aims to reduce emissions from ground transport, boost the use of renewable energy and increase the energy efficiency of airport terminals.

BBC: Airports doing more to go green