Worldwide, hundreds of thousands of students and sympathizers are on the move for the start of the largest series of climate protests ever planned. In the run-up to the United Nations climate summit, almost 5,000 events are taking place in nearly 150 cities around the world until 27 September.

Climate activist Ralyn 'Lilly' Satidtanasarn (12) leads a 'die-in' at the building of the Thai Ministry of Environment , where protesters pretend to be dead. (Photo: Getty Images)

The protest week lasts until 27 September. A major strike in the Netherlands is also planned on that day. (Photo: Reuters)

High school students demonstrate in the Bangladeshi capital Dhaka. (Photo: Getty Images)

Protesters in the Australian city of Sydney, where more than 80,000 demonstrators are on the move. More than 100,000 climate activists argue in Melbourne. (Photo: Getty Images)

Demonstrators in Brisbane, where 30,000 demonstrators took to the streets. (Photo: Getty Images)

A girl argues in Sydney. The school strikes originally started a little less than a year ago in Sweden, inspired by climate activist and student Greta Thunberg. (Photo: Getty Images)

Thunberg is now in New York, where the now world-famous activist has sailed with a sailing ship to make people aware of the climate crisis. (Photo: Getty Images)

A climate activist in the Indonesian town of Palangkaraya receives oxygen from a fellow demonstrator. There is a lot of smog in the city due to nearby forest fires. (Photo: Reuters)

Protesters in Indonesia. (Photo: Getty Images)

In Tokyo, the discussion about nuclear energy also plays a role in climate protests. (Photo: Getty Images)

In Berlin, three activists symbolize the climate crisis with a sling around their necks while standing on melting blocks of ice. (Photo: Reuters)

Activists in the South African city of Cape Town. (Photo: Reuters)

Protesters in the Polish city of Lublin. (Photo: Reuters)