Tehran switched off the lights on Milad Tower and Azadi Tower, two iconic buildings in the Iranian capital, at 2030 local time (1630GMT) to mark this year’s Earth Hour.
The global event, started in 2007, is organized by environmental group World Wildlife Fund (WWF) to push for action on climate.
Earth Hour saw other cities, including Berlin, Paris, Bangkok and Athens, engaging in the event by turning off the lights on their iconic monuments at 2030 local time.