Earth Day 2011: World's major cities turn off their lights

For one hour last Saturday, people around the world took part in the fifth annual Earth Hour. Over a period of 60 minutes (from 8:30 to 9:30pm local time), non-essential lights were turned off across the seven continents in an effort to "take a stand against climate change."

Individuals, households, corporations and cities clicked their light switches to the "off" position, raising not only global awareness but also providing for some pretty stunning photographs. Have you ever wondered what the Eiffel Tower looks like without its lights on? What about the Empire State Building?

Take a look at the amazing photos from around the world below.

Did you turn your lights off?