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

Since beginning in Sydney in 2007, the annual event has spread to more than 180 countries, with tens of millions of people joining in, from turning off the porch lights to letting the Opera House go dark.

Those 60 minutes are “an opportunity to adopt a shifting of the consumption culture, and behaviour change towards sustainability”, Indian environment minister Harsh Vardhan said in a statement.

A view of the building of Vajdahunyad Castle with its illumination switched off to mark Earth Hour, in Budapest, Hungary. Photograph: Tamas Kovacs/EPA

Many people barely noticed. Around India Gate, New Delhi’s monument to the Indian dead in the first World War, thousands of people continued with their typical nightly warm-weather activities. They bought ice cream and cheap plastic trinkets and flirted, while young children rode in electric carts that their parents rented for a few minutes at a stretch.

The scene was repeated over and over across the world: at Sydney’s Opera House, at Kuala Lumpur’s Petronas Towers, at Edinburgh Castle in Scotland

But for an hour the arch stayed dark, a silent call for change.

In Jordan, the Royal Society for the Conservation of Nature arranged 11,440 candles on a hilltop in the capital of Amman, establishing a Guinness World Record for the largest candle mosaic.

The candles spelled out the Earth Hour motto of “60+”. However, attempts to light the candles largely failed because of wind on the hilltop, which is close to the city’s landmark, the Amman Citadel.

Buckingham Palace in London after it switched off its lights for an hour to mark Earth Hour to raise awareness about climate change. Photograph: Jonathan Brady/PA Wire

In Paris, the Eiffel Tower went dark, while in London, a kaleidoscope of famous sites switched off their lights – Tower Bridge, Big Ben, Piccadilly Circus and the London Eye.

The scene was repeated over and over across the world: at Sydney’s Opera House, at Kuala Lumpur’s Petronas Towers, at Edinburgh Castle in Scotland, at Brandenburg Gate in Berlin and at St Basil’s Cathedral in Moscow. – Associated Press