Global landmarks including the Eiffel Tower in Paris and Sagrada FamÃlia Basilica in Barcelona switched off their lights for an hour on Saturday night to mark Earth Hour.
The global event, organised by the World Wide Fund for Nature, takes place every year to raise environmental awareness.
It aims to encourage people to turn off their lights for 60 minutes and the event first started in Sydney, Australia, in 2007.
Video journalist: Emaan Warraich