Athens  - Lights went out on the Acropolis for Earth Hour 2009, and hundreds of residents in the Athens neighborhood of Plaka walked around with lanterns beneath the ancient rock for an hour to highlight the threat from climate change.

Environmental group WWF, which started the global event to turn out the lights at prominent landmarks, homes and businesses, is hoping 1 billion people will take part this year to draw attention to climate change.

Nearly 50,000 residents in 400 municipalities and 1,000 businesses were estimated to participate across Greece in the global event, organizers said. The presidential palace, the parliament building and a runway at Athens' International Airport also switched off their lights.

Aside from the ancient Acropolis, the lights were also dimmed at the temple of Posidon in Sounion as well as the Temple of Athena Lindia on the Dodecannese island of Rhodes.

Other Greek landmarks which turned off their lights for an hour included the Olympic Stadium, site of the 2004 Summer Games, as well as the Rio-Antirion bridge, the longest suspended bridge of its kind which connects the Peloponnese with mainland Greece. (dpa)