Earth Hour 2011, an Earth Day celebration, is upon us and “more than 120 countries participate in turning off lights for 60 minutes from 8:30 to 9:30 in the evening local time in an effort to raise global awareness on climate change.” Video after the break. Click here for more pictures.

Now in its fourth year, Earth Hour promises to be the biggest ever, organisers said, with thousands of cities and towns in 125 countries – 37 more than last year – pledging to take part following last year’s failed climate talks.

[via HuffingtonPost]