Earth Hour was celebrated in more than 7,000 cities, towns and villages in over 150 countries. An impressive number of the world's best known landmarks went dark for the hour - from the Kremlin in Moscow to the Empire State Building in New York.
But most importantly, Earth Hour is the inspiration behind so many 'beyond the hour' activities and pledges to help tackle climate change and protect the natural environment.
People from all walks of life and backgrounds went to amazing lengths to share what the planet means to them and what they're willing to do to protect it.
As WWF director general Jim Leape summed it up, "Earth Hour has created a global community, and together we really can make a difference."
In the UK we ran a live online broadcast of Earth Hour events for the first time ever. You can relive the UK's Earth Hour Live experience - including a live acoustic gig by McFly.
Earth Hour around the world
Here's some video snippets of Earth Hour switch-offs as they came in from around the world on Saturday night...
Russian supporters, who last year helped secure a law against oil pollution at sea, now have more than 100,000 signatures on a new petition calling for forest protection.
In Madagascar WWF and Earth Hour partners handed out 1,000 wood-saving stoves to victims of February's cyclone Haruna, saving families money while reducing impacts on forests.
Villages in India that haven't had electricity are now being lit up with solar energy for the first time, thanks to Earth Hour initiatives.
In Libya, Earth Hour participants took on an 80km walk from Gharyan to the capital Tripoli.
Countries across the world have used Earth Hour as a way to engage children in environmental issues, working with initiatives like Green Schools in Indonesia and the Low-Carbon School Network in Thailand.
Also with the focus on younger supporters, there was a rap concert in Benghazi in Libya, a rock concert in Nepal's second largest city Pokhara, a band concert in Malaysia's capital Kuala Lumpur, a free reggae show in Kingston Jamaica, and performances in Hanoi and Vietnam, among many other places.
In Singapore, where there's a drive to reduce the country's energy consumption by cutting back on air conditioning, a dancefloor completely powered by kinetic energy generated enough power for an outdoor cinema.
Canadian astronaut Commander Chris Hadfield and Russian cosmonaut Roman Romanenko both sent messages and images from space, with their unique perspective of seeing Earth from above, with all its natural wonders and energy-guzzling cities. The message was about how much we depend on this beautiful and fragile planet - and how its health depends on us too.
Places participating in Earth Hour for the first time included Palestine, Suriname, Rwanda and Tunisia, birthplace of the Arab Spring.
Vancouver in Canada was announced as the first ever Global Earth Hour Capital, recognised unanimously by a jury of experts for its innovative actions on climate change and dedication to creating a sustainable, pleasant urban environment - for instance their aim is for all new buildings to be carbon neutral by 2020.
Celebrities endorsing Earth Hour 2013 included Lionel Messi, Yoko Ono, Jessica Alba, Imogen Heap and more. Anti-apartheid hero Nelson Mandela was one of the first to tweet his support for Earth Hour on the night, and he emphasised the importance of forests in our world, saying: The trees & forests were destroyed exactly because our people were so dependent upon them as sources of energy."
Tens of thousands of Earth Hour images were uploaded online on the night too.
Thank you to everyone who was part of WWF's Earth Hour 2013. It's not too late to sign up to show your support.
Earth Hour will be back next year on Saturday 29 March!