Cities around Asia were turning out the lights Saturday evening to mark the 10th annual Earth Hour, a global movement dedicated to protecting the planet and highlighting the effects of climate change.

In Seoul, the glass-covered City Hall was among several public buildings where officials switched off the lights inside and out. Lights illuminating landmarks such as the massive COEX shopping mall, the city's main railway station and several bridges on the Han River were all either turned off or dimmed.

Other cities across Asia were also turning off the lights for the hourlong event, held at 8:30-9:30 p.m. local time. Cities from other regions around the world will follow later Saturday.

The first Earth Hour event was held on March 31, 2007, when the WWF conservation group inspired people in Sydney to turn out the lights for an hour. Since then, the WWF-organized event has expanded to thousands of cities and towns around the world and has been held every March.