Photos: Cities worldwide turn off their lights to mark Earth Hour 2023

A view of the Supertree Grove structures at Gardens by the Bay before and after lights are switched off to mark Earth Hour, in Singapore. | Earth Hour, which WWF organises, encourages people worldwide to turn their lights off for 60 minutes to raise awareness about environmental issues.

The Sydney Opera House before and during Earth Hour, in Circular Quay, Sydney, Australia. | Participants turn off lights in residential buildings as well as the illumination of famous city landmarks and monuments for one hour between 8:30 and 9:30 p.m. local time.

The Sydney Harbour Bridge | Earth Hour is an annual international event, which has been held since 2007 on the last Saturday in March by the World Wide Fund for Nature.

Namsan Seoul Tower illuminated before (L) and after (R) the lights were turned off to mark the Earth Hour environmental campaign in Seoul, South Korea.

Seoul City Hall illuminated before (top) and after (bottom) the lights were turned off to mark the Earth Hour environmental campaign in Seoul, South Korea.

Quezon Memorial Shrine before and after the lights were turned off to mark the Earth Hour environmental campaign in Quezon city, suburban Manila, Philippines.

A combination picture shows the Temple of Dawn before and during Earth Hour, in Bangkok, Thailand.

A combination picture shows a view of the Hong Kong's Central financial district before and after lights are switched off to mark Earth Hour, in Hong Kong, China.

Kuala Lumpur's skyline with Petronas Twin Tower at the centre, during and after observing Earth Hour, in Kuala Lumpur, Malaysia.