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 fan gestures next to a police officer while celebrating the life of British singer Keith Flint of techno group “The Prodigy” after his funeral in Braintree, Essex, Britain, March 29, 2019. (Photo by Henry Nicholls/Reuters)

Members of the Coney Island Polar Bear Club warm up before swimming at the beach at Coney Island in New York, December 15, 2013. (Photo by Eric Thayer/Reuters)

A picture made available on 08 July 2015 showsa lightning strikes during a heavy storm over Poznan in the night of 07 July 2015. Severe storms passed last night over Poland causing lots of damages to buildings, trees, electricity and railway tractions. (Photo by Lukasz Ogrodowczyk/EPA)

The driver of a Maerlitram (fairy tram), dressed as a Santa Claus, walks past a car which crashed into the tram in Zurich, Switzerland December 7, 2017. (Photo by Angelika Gruber/Reuters)

A female pitch invader is caught by a steward during Day Two of the Fourth Test between South Africa and England at Wanderers on January 25, 2020 in Johannesburg, South Africa. (Photo by Stu Forster/Getty Images)

Lightning strikes during a storm over the promenade of Palma de Mallorca, Balearics, Spain, on November 4, 2017. Mallorca and Menorca were in yellow alert because of heavy rain and violent winds. (Photo by Cati Cladera/EPA/EFE)

Children take part in the “Carnavalito” children's parade during the Blacks and Whites Carnival in Pasto, Colombia, on January 2, 2018. (Photo by Juan Barreto/AFP Photo)