Millions of young people flooded the streets of cities around the world on Friday to demand political leaders take urgent steps to stop climate change, uniting in a worldwide protest inspired by 16-year-old Swedish activist Greta Thunberg.

Alarmed by images of the Greenland ice sheets melting and the Amazon rainforests burning, students and workers abandoned schools, shops and offices in nearly every corner of the globe, aiming to stop what they see as a looming environmental catastrophe.