Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)

A demonstrator is carried during a rally in support of a identity check draft law and against delinquency, in Santiago, Chile April 30, 2016. (Photo by Carlos Vera/Reuters)

“In anatomy, heterochromia refers to a difference in coloration, usually of the iris (but also of hair or skin). Although infrequently seen in humans, complete heterochromia is more frequently observed in other species, where it almost always involves one blue eye”. – Wikipedia (Photo by StooMathiesen)

A woman reacts after she was hit with pepper spray deployed by police as they cleared a street with protesters rallying against a new national security law in Hong Kong on July 1, 2020, on the 23rd anniversary of the city's handover from Britain to China. A man found in possession of a Hong Kong independence flag became the first person to be arrested under Beijing's new national security law for the city, police said on July 1. (Photo by Dale De La Rey/AFP Photo)

Protesters a demonstration of the LGTBI collective in Madrid on November 20, 2021 against the rise of the fascism in the society and in support of the new transgender law in Spain. (Photo by Celestino Arce Lavin/ZUMA Press Wire/Rex Features/Shutterstock)

Belarusian law enforcement officers detain a woman during an opposition rally to protest against police brutality and to reject the presidential election results in Minsk, Belarus on September 19, 2020. (Photo by Tut.By via Reuters)

Kazakh law enforcement officers detain a woman during a protest rally by opposition supporters in Nur-Sultan on September 21, 2019. (Photo by Orken Zhoyamergen/Radio Free Europe/Radio Liberty)

Law enforcement carry a pro-Palestinian protester at the University of Texas, during the ongoing conflict between Israel and the Palestinian Islamist group Hamas, in Austin, Texas on April 24, 2024. (Photo by Nuri Vallbona/Reuters)