Countries around the world have switched off the lights for Earth Hour, a global call for international unity on the importance of climate change.

Earth Hour 2018
Buckingham Palace in London… (Jonathan Brady/PA)
Earth Hour 2018
…took part in the Earth Hour campaign (Jonathan Brady/PA)
Earth Hour 2018
Piccadilly Circus in London was also left in the dark (WWF/PA)
Earth Hour 2018
Tower Bridge in London before… (WWF/PA)
Earth Hour 2018
…and after it switched off its lights (WWF/PA)
Jordan Earth Hour
Jordanians light candles that form the Earth Hour logo, in an official attempt to be registered in the Guinness Book of Records for the largest candle-shaped World Hour logo, in Amman (Raad Adayleh/AP)
Jordan Earth Hour
The Royal Society for the Conservation of Nature arranged 11,440 candles on a hilltop in the capital of Amman (Raad Adayleh/AP)
Jordan Earth Hour
The candles spelled the Earth Hour motto of ’60+’ (Raad Adayleh/AP)
Hungary Earth Hour
The Millennium Monument, a landmark of the Hungarian capital with its illumination switched on prior to the Earth Hour event… (Tamas Kovacs/MTI via AP)
Hungary Earth Hour
…and the same monument with its illumination switched off (Tamas Kovacs/MTI via AP)
India Earth Hour
The landmark India Gate monument is seen lit, top, and then in darkness after the lights were turned off for one hour (Oinam Anand/AP)
Philippines Earth Hour
A Filipino girl plays with a light toy in observance of Earth Hour (Bullit Marquez/AP)
Philippines Earth Hour
The globe landmark of the Philippines’s largest shopping mall, the Mall of Asia, turns dark for Earth Hour (Bullit Marquez/AP)