Greta Thunberg

Hundreds of school pupils took part in a demonstration against climate change outside Parliament in downtown Athens on Friday.

The start was in Australia, where thousands of students did not enter classrooms today.

The youth gathered in central Sydney and called on large corporations and Australian governments to take urgent action against climate change.

The processions have already started in many European cities, with a total of 150 countries expected.

Swedish teenage climate activist Greta Thunberg will set sail for New York this week, crossing the Atlantic in a racing yacht to join protests in the United States and take part in a United Nations summit.

Greek students holding placards and shouting slogans take part in a "youth strike to act on climate change" demonstration in front of Parliament in Athens, Friday. Thousands of students around the globe, mobilized by word of mouth and social media, skipped class to demonstrate the failure of political elites to take action against global warming.

Dozens of students in Athens, Thessaloniki and other Greek cities on Friday gathered at central points to call for action against climate change, joining their voices to a global movement called #fridaysforfuture.