Cities across the world were plunged into darkness for an hour last night to mark Earth Hour 2015.

The global event is designed to raise awareness about climate change.

Landmarks including the Houses of Parliament, the Eiffel Tower, Sydney Harbour Bridge and St Basil’s Cathedral in Moscow dimmed their lights to highlight the need for change in environmental policy.

It was established in in 2007 in Australia by WWF and is now celebrated in more than 100 countries, as well as in Antarctica and the International Space Station.

Environmentally friendly Berlin turned off the lights for Earth Hour (Reuters)

St Basil's went dark in Moscow (Reuters)

Fireworks heralded the start of Earth Hour in Sydney (AFP/Getty)

Earth Hour director Sudhanshu Sarronwala said: “Earth Hour confirms our belief that in order to change climate change we need to act together.”

The spiritual home of the world's Catholics dimmed its lights along with other world landmarks (EPA)

The City of Lights went dark for an hour (EPA)

Ban Ki-Moon, the UN secretary general, echoed this in a statement he made on YouTube where he said that people coming together will play a key role in helping to solve climate change.