Photos: Climate change protesters take to the streets around the world

Teen activist Greta Thunberg walks during the Global Climate Strike march in New York on Sept. 20, 2019.

Millions of people are taking to the streets across the world in what could be the largest climate protest in history.

Environmental activists rally in central London.

A student holds at the Experiential School of Greensboro.

Many groups are involved in organizing the strikes including schoolchildren, trade unions, environmental groups and employees at large tech companies such as Amazon and Google, and their demands are all similar: reducing the use of fossil fuels to try to halt climate change.

Activists gather in John Marshall Park. 

Students hold up signs during the Global Climate Strike march at Foley Square.

The demonstrations are timed to nearly coincide with Monday’s U.N. Climate Summit in New York, where United Nations Secretary-General Antonio Guterres has said he wants to see governments and businesses pledge to abandon fossil fuels.

A young woman holds up a banner during a march in Skopje, Macedonia against climate change.

Students take part in a march from Wageningen to The Hague, in Wageningen, The Netherlands.

The students took a week off from education to draw attention to climate policy on a walking tour.

Young people listen to speakers. 

Activists stand on blocks of ice under makeshift gallows in front of the Brandenburg Gate. 

People attend a Fridays For Future rally.

“The climate crisis is an emergency — we want everyone to start acting like it. We demand climate justice for everyone,” organizers said on one website dedicated to Friday’s protests, which said there was action planned in more than 150 countries.

Protesters gather at Brussels-North Station with placards.

New Delhi, one of the world's most polluted cities, saw dozens of students and environmental activists chant "we want climate action."

A large inflatable globe is bounced through the crowd as thousands of protesters, many of them school students, gather in Sydney.

Young children in traditional dress representing the Pacific Islands get ready to march.

Young activists march as part of the movement Fridays for Future.

Hundreds marched in Thailand's capital Bangkok, before staging a "die-in" outside the Ministry of Natural Resources.

A woman puts her face through a banner at an event to mark the day of global climate strikes.

A youth inhales an oxygen can as he is treated during a rally as smog covers the city due to the forest fires in Palangka Raya, Central Kalimantan province, Indonesia.

Australia saw some of the first protests kick off Friday morning with organizers estimating that upwards of 300,000 students and workers filled the streets of Melbourne, Sydney and other cities in the biggest protests the country has seen in years.