Earth Hour 2012
What will you be doing when the lights switch off? World Wildlife Fund's Earth Hour is well-known for its huge landmark switch offs - this year the Houses of Parliament, Buckingham Palace and Old Trafford Stadium are just a few of the big names taking part again. But what it's really about is people coming together to celebrate and show we care about our brilliant planet.
There's loads happening across the country, from candlelit dinner parties and torchlit treasure hunts to environmental workshops and acoustic gigs - there's even an Earth Hour wedding! But don't worry if you haven't got plans because there's still time to get involved.
Check out the WWF Earth Hour website for more ideas about how to get involved.