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 young girl tries to catch snow on her tongue near the Martin Luther King Jr. Memorial, before the start of a wreath-laying ceremony honoring the legacy of the late civil rights leader in Washington, DC on January 15, 2024. The ceremony is being held to honor the civil rights leader on the anniversary of his birthday. (Photo by Andrew Caballero-Reynolds/AFP Photo)

A man dressed in a condom costume walks at Caleta Portales beach, during a summer awareness campaign by the Chilean Corporation for the Prevention of AIDS in Valparaiso city, northwest of Santiago January 9, 2015. (Photo by Rodrigo Garrido/Reuters)

Residents carry a slaughtered pig with a bamboo pole as they walk home on a street, which was shut to traffic due to ice, in Leishan county, Guizhou province January 31, 2015. Blizzards and icy rain that lasted for several days at the end of January have disrupted traffic, collapsed houses and decimated crops in central Chinese provinces, Xinhua News Agency reported. (Photo by Reuters/Stringer)

A protester lies on the ground after being pushed during a protest over coronavirus disease (COVID-19) restrictions in mainland China, during a commemoration of the victims of a fire in Urumqi, in Hong Kong, China on November 28, 2022. (Photo by Tyrone Siu/Reuters)

An Iraqi special forces soldier shot dead an Islamic State suicide bomber in Mosul, Iraq March 3, 2017. (Photo by Goran Tomasevic/Reuters)

The entire cast perform during a production media call for Singin' In The Rain at Her Majesty's Theatre on May 12, 2016 in Melbourne, Australia. (Photo by Robert Cianflone/Getty Images)

Dancers from the British theater company Motionhouse perform a show with excavators entitled “Traction” on the Prado beach in Marseille, France, on May 10, 2013. (Photo by Boris Horvat/AFP Photo)