Animals destined for the stage of Radio City Music Hall in New York on November 13, 1986 are led to the stage door by their co-stars, the Rockettes dancers. A variety of animals, including camels, sheep and donkeys, will star in an annual Christmas production. (Photo by G. Paul Burnett/AP Photo)

Jourdan Dunn poses for photographers upon arrival at the MTV European Music Awards 2016 in Rotterdam, Netherlands, Sunday, November 6, 2016. (Photo by NIVIERE/SIPA Press/Rex Features/Shutterstock)

Boys walk near a damaged building in the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria December 30, 2016. (Photo by Bassam Khabieh/Reuters)

A man assist trucks carry palm oil fruit on a damaged road at Mesuji Raya village in Ogan Komering Ilir, South Sumatra province, Indonesia, January 11, 2017. (Photo by Budi Candra Setya/Reuters/Antara Foto)

Kandy Freeman participates in a Black Lives Matter protest in front of Trump Tower in New York City, U.S. January 14, 2017. (Photo by Stephanie Keith/Reuters)

A spectator cools herself at a water spraying fan at the Australian Open tennis championships in Melbourne, Australia, Tuesday, January 17, 2017. (Photo by Kin Cheung/AP Photo)

Janelle Monae (L) and Taraji P. Henson pose with the SAG Award for Outstanding Cast in a Motion Picture award for “Hidden Figures”, during the 23rd annual Screen Actors Guild Awards ceremony at the Shrine Exposition Center in Los Angeles, California, USA, 29 January 2017. (Photo by Paul Buck/EPA)

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)