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)

Miss USA Alyssa Campanella arrives at the 2nd Annual American Giving Awards at the Pasadena Civic Auditorium on December 7, 2012 in Pasadena, California. (Photo by Gregg DeGuire/WireImage)

Revellers wearing lanterns parade through the streets during the carnival procession of Basel, Switzerland, 15 February 2016. The traditional Morgestraich starting Monday morning after Ash Wednesday at 4 a.m. marks the kick-off of the Carnival of Basel. (Photo by Patrick Seeger/EPA)

Sweepee Rambo, a Chinese Crested, is presented to judges during the World's Ugliest Dog Competition in Petaluma, California on June 26, 2015. (Photo by Josh Edelson/AFP Photo)

Transgender contestants run backstage before the final of the annual Miss Tiffany's Universe 2014 transvestite contest in the beach resort town of Pattaya, May 2, 2014. The contest aims to promote a positive image of transvestites. (Photo by Athit Perawongmetha/Reuters)

Emily Ratajkowski is seen at “Jimmy Kimmel Live” on August 07, 2017 in Los Angeles, California. (Photo by Rex Features/Shutterstock)

Miss Puerto Rico Stephanie Del Valle (C) reacts after winning in the Grand Final of the Miss World 2016 pageant at the MGM National Harbor December 18, 2016 in Oxon Hill, Maryland. (Photo by Zach Gibson/AFP Photo)

Arctic wolves in their new enclosure in the wildlife park in Hanau, Germany, 10 February 2015. The pack is one of the park's main attractions, which specializes in local and European breeds. (Photo by Boris Roessler/EPA)