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)

Rwandan refugees cross the Rusumo border to Tanzania from Rwanda carrying their belongings, goats, mattresses and cows, May 30, 1994. The bloodshed that claimed 800,000 Tutsi and moderate Hutu lives began 25 years ago on April 7, 1994, when a plane carrying Rwandan President Juvenal Habyarimana, Burundi President Cyprien Ntaryamira and a French air crew was shot down. (Photo by Jeremiah Kamau/Reuters)

A man wearing an aquarium with goldfishes on his head walks among the pedestrians at the “Village de Saint-Malo”, the start point of the Route du Rhum solo sailing race, in Saint-Malo on November 1, 2022. The Route du Rhum solo sailing race starts on November 6, 2022, from Saint-Malo to Pointe-a-Pitre in Guadeloupe. (Photo by Loic Venance/AFP Photo)

Victor Peralta from Uruguay gestures during the fourth International Tattoo Convention in Quito, September 25, 2016. (Photo by Kevin Granja/Reuters)

A person dressed as an astronaut walks past a man stopping traffic on a pedestrian crossing outside the Sydney Exhibition Centre September 13, 2014 where the science-fiction convention called “Oz Comic-Con” is currently being held. The two-day convention showcases “pop culture”, and includes appearances by actors from science-fiction movies and television shows. (Photo by David Gray/Reuters)

Hannan Iskandar gets ready before she starts to drive her car in her neighborhood, in Al Khobar, Saudi Arabia on June 24, 2018. Saudi Arabia ended its longstanding ban on women driving on June 24, 2018 – and the second the clock struck midnight, women across the country started their engines. (Photo by Hamad I Mohammed/Reuters)

Greek actress Xanthi Georgiou, playing the role of the High Priestess, lights up the torch during the flame lighting ceremony for the Beijing 2022 Winter Olympics at the Ancient Olympia archeological site, birthplace of the ancient Olympics in southern Greece on October 18, 2021. The Olympic flame will once again be lit in an empty stadium on Ovtober 18, 2021, as it starts its truncated journey to Beijing for the Winter Games in February. Like the ceremony in March 2020 to light the flame for Tokyo, and like those Games, which were put back a year, Monday's ceremony is a victim of coronavirus restrictions. (Photo by Aris Messinis/AFP Photo)