Cities and communities around the world are getting ready to switch off their lights in a powerful and united statement to world leaders that they need to take immediate action on climate change.
At 8 p.m. local time today, some of the world's most iconic landmarks will disappear from city skylines as millions of people all across the globe take part in Earth Hour.
At the last count, there were around 380 cities and communities supporting the event. Chicago, Denver, Atlanta, and San Francisco are all set to take part, along with London, Manila, Sydney, Bangkok, Vancouver and Tel Aviv, among other cities.
"Earth Hour shows that everyday people are prepared to pull together to find a solution for climate change," said James Leape, the general director of World Wildlife Fund International, the global organizer of Earth Hour.
"It can be done, but we need to harness some of the cooperative spirit we've seen with Earth Hour to find a global solution," he continued.
"The challenge now is to build on the momentum Earth Hour has created, to use it to propel us forward."
Leape reminded people that although it may seem like a bit of fun, there is a serious message behind the lights out.
"It is time that governments around the world matched the concerns of their citizens with actions, for corporations to cut their carbon emissions, and for individuals to do what they can to reduce energy consumption," he said.
Some of the global landmarks getting ready for the hour-long blackout are the Sydney Opera House and Sydney Harbour Bridge, the Golden Gate Bridge in San Francisco, Niagara Falls in Canada and the Colosseum in Rome. The Australian Antarctica base station Casey will also switch off its lights for one hour.
"On Earth Hour, individuals, households and businesses have an opportunity to stand on the world stage alongside our most magnificent iconic landmarks, and to have it known that we can make a real impact in the fight against climate change if we stand together," said Earth Hour Executive Director Andy Ridley.
"The health of the planet is a shared concern, and solving the problem of climate change is something that can truly unite us as a global community."