Thousands of school students from around the world walked out of their classes to join a global protest against inaction on climate change.
This was the scene in Rome, Seoul, Sydeny, London, Berlin and more, all cities that have seen thousands line their streets.
More demonstrations are planned later in the day in the United States.
Organizers claim about 2,500 students should attend a rally in Washington.
(SOUNDBITE) (French) 19 YEAR-OLD STUDENT, JULIETTE, SAYING: "What worries me is that really horrible phenomena are already happening in other countries.
Here in Switzerland, we are not yet being hit that much -- even if last summer was extremely hot, it had been years since it was that hot here, and really it is a problem." Support from international leaders is mixed.
New Zealand Prime Minister Jacinda Ardern, for example, supports it.
She says teens shouldn't wait for voting age to speak up.
On the other side: Australian and British politicians have said they shouldn't be cutting class.
(SOUNDBITE) (Italian) 14-YEARS-OLD ACTIVIST, MATILDE MARINO, SAYING: "We are here because we are afraid for our future.
They tell us that in eleven years we could die and that what we are studying now will be useful for our future.
If we do not have a future why should we study?" The movement was sparked last August by a 16-year-old Swedish student, Greta Thunberg, when she began protesting outside her parliament on school days.
Thunberg has since been nominated for the Nobel Peace Prize.