Canadian astronaut Commander Chris Hadfield, currently on board the International Space Station, has been tweeting images of major cities prior to Earth Hour.
He wrote, "New York City, lit up like a bulb. The Statue of Liberty is clearly visible in the night from above".
The commander also highlighted that "spiderwebs of light expanding out from the dark river border" could be seen of Detroit and Windsor.
More top news
Bargain hunters will be out in force today. Find out which shops have the best offers.
The new scheme also aims to help prevent the growth of diabetes, of which there are three million sufferers in the UK.
Up to 10cm of snow could hit parts of Britain today as forecasters predict a cold snap in the lead-up to the New Year.