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.
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Nicola Sturgeon will today pledge that her party will work with others to bring about "positive change" for ordinary people across the UK.
Half of teachers said the number of youngsters dealing with difficulties, such as depression, has risen compared to two years ago.
David Cameron will use a speech today to set out plans for patients to be able to access hospital services seven days a week.