The global climate strikes of 20 to 27 September 2019 were among the largest protests the planet had seen. Organisers counted millions of marchers in more than 150 countries, many of them too young to vote.
The idea had started with one student sitting outside a parliament on Fridays. A year later, whole city centres closed to traffic as crowds of every age gathered behind hand-painted signs. These pictures follow the week across four continents.
