Earth Hour is a global action against climate change.
It started in Australia in 2007 and it has grown to a global day of action. Last year 135 countries across every continent took part.
Organisers hope this year will be even more successful.
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Around 40 events will be staged across the UK today as nurses step up their campaign for the Government to end the cap on public sector pay.
Within the next seven days, we are going to witness some of the most significant change in the British Monarchy for many years.
Prince William is set to complete his final air ambulance pilot shift before taking taking up royal duties full-time.