Teenagers and yound adults demonstrated in 2,052 locations in 123 countries across all continents, including Antarctica, claimed 16-year-old Greta Thunberg on Twitter; sharing this picture from Sydney. Credit: @GretaThunberg/TwitterProtesters in Hong Kong under the banner of #FridayForFutures demand stronger action to combat climate change. Such demonstrations in cities across the globe were inspired by Thunberg's sit-ins outside the Swedish Parliament which begain in August 2018. Photo: @LeungRrachel/TwitterStudents in Dortmund, Germany, join the #FridaysforFuture demonstration at Friedensplatz in the city centre. The mayors of Paris, Milan, Sydney, Austin, Philadelphia, Portland, Oslo, Barcelona & Montreal have indicated in a statement that they want to hear ideas from the youth about how to tackle climate change. Photo: @julentek/TwitterStudents in Philippines demand climate justice. Photo: @Greenpeace/Twitter#FridaysForFuture in Prague. Photo: @centrum_klinika/TwitterSchool strike in Melbourne, Australia. Photo: @Greenpeace/Twitter