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 soldier from the South Korean army special forces breaks stone plates with her head during a martial arts demonstration for Memorial Day at Korea War Memorial Museum in Seoul, South Korea, Monday, June 6, 2016.(Photo by Ahn Young-joon/AP Photo)

A man lying on the ground is assisted by French policemen during clashes bewteen English and Russian supporters in the Old Port of Marseille, France, Saturday, June 12, 2016, before the UEFA EURO 2016 group B match between England and Russia. (Photo by Daniel Dal Zennaro/ANSA via AP Photo)

Sandra Brown, 40, rides the Skyslide on the 69th and 70th floors of the U.S. Bank Tower which is attached to the OUE Skyspace LA observation deck in downtown Los Angeles, California, U.S. June 20, 2016. (Photo by Lucy Nicholson/Reuters)

“Joker” movie production tries to hide Joaquin Phoenix's clown make-up and green hair with umbrella and a long black cloth over his head as he was walking with the help of assistant and bodyguard to the set of “Joker” filming at a Bronx train station on September 22, 2018. (Photo by The Mega Agency)

People enjoy carnival while shouting slogans of female empowerment and anti harrassment in Sao Paulo, Brazil on January 28, 2018. The carnival is marked by a lot of fun, but also has space to talk about more serious things – without losing the good mood. Parading for the first time in São Paulo, the Vaca Profana block proposed a reflection on sieges and machismo. (Photo by Cris Faga/Rex Features/Shutterstock)

In this image released on October 1, model Jazzelle Zanaughtti is seen onstage during Rihanna's Savage X Fenty Show Vol. 2 presented by Amazon Prime Video at the Los Angeles Convention Center in Los Angeles, California; and broadcast on October 2, 2020. (Photo by Jerritt Clark/Getty Images for Rihanna's Savage X Fenty Show Presented by Amazon Prime Video)