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 woman cleans her boat after a snowfall in Srinagar, December 13, 2019. (Photo by Danish Ismail/Reuters)

Models present creations from the Michael Kors spring summer 2023 collection during New York Fashion Week in Manhattan, New York City, U.S., February 14, 2023. (Photo by Caitlin Ochs/Reuters)

An undated handout photo made available by the Zerynthia Association shows the pupa of an amicta moneiba, a recently discovered species of moth endemic to La Gomera and El Hierro islands in the Canary Islands, Spain (issued 01 July 2020), as those two islands pulled apart from the rest of the Canary Islands 2.5 million years ago. The Institute of Evolutionary Biology of the Spanish National Research Council (CSIC) and the Zerynthia Association have recently discovered two new moth species in El Hierro and La Gomera. (Photo by Yeray Monasterio/Zerynthia/EPA/EFE)

Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

Fireplace for children, Trondheim, Norway, by Haugen/Zohar. The children of Trondheim come to sit around the fire and tell stories in this whimsical cone hut, made with materials recycled from a construction site. (Photo by Jason Havneraas/The Guardian)

A Tamil devotee lights an oil lamp at a religious ceremony during the Diwali or Deepavali festival at Ponnambalavaneshwaram Hindu temple in Colombo, Sri Lanka on October 24, 2022. (Photo by Dinuka Liyanawatte/Reuters)

Israeli soldiers play the parts of wounded civilians during a drill simulating a toxic spill from an attack on a train in Beersheba, southern Israel, 13 January 2016, as Home Front medical teams, fire fighters and police carry out rescue operations. The large scale drill is the concluding exercise of the Fourth International Conference on Healthcare System Preparedness and Response to Emergencies and Disasters and includes some 200 of the world's experts on health system readiness from around the world. The conference is dealing with all types of medical emergencies from terrorist attacks to natural disasters. (Photo by Jim Hollander/EPA)