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 reveler, dressed as a Brazilian national army soldier holding a mock weapon with flowers jutting out of it, participates in the annual Gay Pride Parade in Sao Paulo, Brazil, Sunday, June 18, 2017. (Photo by Nelson Antoine/AP Photo)

South Korean rescue members wearing chemical protective suits walk past a monster character (R) during an anti-terror drill as part of a disaster management exercise at the COEX shopping and exhibition center in Seoul on May 20, 2016. South Korea is holding its 2016 Safe Korea anti-disaster exercise this week against terrorist threats and natural disasters. (Photo by Jung Yeon-Je/AFP Photo)

Auditioning performers follow resident choreographer Erik Sorensen, center back, at the Sydney Dance Company in a routine during castings in Moulin Rouge's current show “Féerie”, in Sydney, Australia, Thursday, July 28, 2016. The show's artistic team is in Australia to choose new talent to perform with one of the most famous cabarets that has been illuminating Paris since 1889. (Photo by Rob Griffith/AP Photo)

A wounded servicemen of Ukrainian Military Forces looks on after the battle with Russian troops and Russia-backed separatists in Lugansk region on March 8, 2022. The number of refugees flooding across Ukraine's borders to escape towns devastated by shelling and air strikes passed two million, in Europe's fastest-growing refugee crisis since World War II, according to the United Nations. (Photo by Anatolii Stepanov/AFP Photo)

England football fans celebrate in Trafalgar Square as England score their second goal during extra time in the UEFA Euro womens championship final on July 31, 2022 in London, United Kingdom. England take on Germany in the final of The UEFA European Women's Championship, played at Wembley Stadium. (Photo by Chris J Ratcliffe/Getty Images)

Revellers dressed as the Devil take part in a parade to celebrate Saint Nicholas Day (Mikulas) in Prague, Czech Republic on December 5, 2022. Meeting Saint Nicholas, the Aangel, and the Devil, who talk to children and reward those who have behaved well during the year with small presents, is tradition in the Czech Republic before the Christmas holidays. (Photo by Michal Cizek/AFP Photo)

Activists attend a parade to demand rights of gender equality to LGBT community members in Santiago, Chile, November 25, 2017. (Photo by Ivan Alvarado/Reuters)