The United Nations went dark this evening as the Organization turned off the lights at its iconic Headquarters complex in New York and other facilities around the world in observance of Earth Hour, an annual event raising awareness about the need to take action on climate change and promoting sustainable energy consumption.

Organized by WWF, Earth Hour encourages individuals, companies, organizations and Governments to switch off their lights for one hour at 8:30 p.m., local time worldwide, to focus attention on people-driven solutions to protecting the planet and building a bright, sustainable future. This year, there was record participation across 172 countries and territories, beginning with the first lights-out in Samoa and moving across seven continents to Tahiti, WWF said.

In a video message, UN Secretary-General Ban Ki-moon explained:

“Climate change is a people problem. People cause climate change and people suffer from climate change. People can also solve climate change. Earth Hour shows what is possible when we unite in support of our environment.”

The Secretary-General noted that this coming December in Paris, the United Nations will bring countries together to agree a new, universal and meaningful climate accord, culminating a “year of action” on sustainable development.

“By turning out the lights, we highlight that more than one billion people lack access to electricity. Their future well-being requires access to clean, affordable energy,” said Mr. Ban, stressing that with the world”s lights being switched off, Earth Hour shows what is possible when the international community unites in support of a cause.

First launched in 2007, Earth Hour has become an annual event, mobilizing hundreds of millions of individuals to participate and growing to become the world”s largest grassroots movement for the environment.

According to WWF, the UN family joined thousands of homes, offices, skylines and monuments going dark as the world united to inspire collective action to change climate change.

Over 1,200 landmarks such as the Eiffel Tower in Paris and the Golden Gate Bridge in San Francisco turned off their lights to mark Earth Hour 2015. Close to 40 UNESCO World Heritage Sites including the Acropolis in Athens and Edinburgh Castle in Scotland also supported the initiative.