Chicago landmarks turn off lights for Earth Hour 2012

CHICAGO, Ill. -- Helping save the world.

Some say it's as simple as turning out a light, but Chicago and other cities around the world took it a step further by turning out the lights at some of their biggest landmarks for one hour.

At 8:30 local time Saturday night, Wrigley Field, the Willis Tower and Navy Pier turned off the lights to observe earth hour.

The annual event raises awareness for climate change.

"Generating electricity causes the emission of greenhouse gases which leads to global warming and we know what that does to the environment. So this is a celebration of the environment," said Vice President Fidel Marquez.

Earth hour started in Australia in 2007. Sunday 147 countries around the globe took part reaching nearly 2 billion people.