A protester reacts as police use water cannon during a demonstration to demand changes in the Chilean education system in Santiago, Chile June 25, 2015. (Photo by Ueslei Marcelino/Reuters)

Demonstrators perform a dance in front of riot policemen during a march called by students to request changes in the education system in Santiago, Chile September 5, 2017. (Photo by Ivan Alvarado/Reuters)

Climate change activist Greta Thunberg reacts during a news conference during COP25 climate summit in Madrid, Spain, December 9, 2019. (Photo by Juan Medina/Reuters)

Ocean Rebellion put on a display of puking oil heads ahead of climate change conference COP26 in Glasgow, Britain, 29 October 2021. (Photo by Robert Perry/EPA/EFE)

Look at the image for long enough and you can make the train change direction simply by thinking about it. Freaky.

Climate change activists dressed up as black birds protest in St. Ives, on the sidelines of the G7 summit in Cornwall, Britain, June 11, 2021. (Photo by Dylan Martinez/Reuters)

A robin perches on a spade handle in a garden on a rainy day in Lixwm, north Wales. Researchers said this week that when European robins are subjected to human-produced noise, their behaviour changes. (Photo by DGDImages/Alamy Live News)

The Invasion. A quiet street in Macau. Modernization around is quickly changing the city, as documented by Paul Tsui. (Photo by Paul Tsui/National Geographic Travel Photographer of the Year Contest)