Thousands of students skipped school for the third week in a row and more than 30,000 gathered in the centre of Brussels on Thursday to demand better protection of the world's climate.
What started out as a march of a few thousand high school students swelled to a mass movement that also included many university students.
Brussels police said around 32,000 people braved the snowy conditions to join the demonstration.
Another climate march is scheduled for Sunday.
