Hungary Earth Hour

The Royal Castle of Buda with its illumination switched on, left, and the illumination switched off, right, to mark Earth Hour, in Budapest, Hungary, on March 24, 2018. Earth Hour is a worldwide environmental campaign that is observed on the last Saturday of March every year, and is a global call to turn off the lights for 60 minutes to raise awareness of the danger of global climatic change. (Marton Monus/MTI via AP)