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)

An Iraqi Muslim woman walks past Christmas decorations for sale in the Shiite holy city of Najaf on December 17, 2015. (Photo by Haidar Hamdani/AFP Photo)

This lemur looks like he is channelling the spirit of Buddha – as he sits meditating. Sitting with his legs crossed, the lemur clasps his thumb and fore finger together with outstretched arms – just like the spiritual teacher. And amateur snapper Sebastien Degardin, 32, was on hand to capture the bizarre moment the animal searched for enlightenment on film. Sebastien, who moved from his native Belgium to Finchley, North London, said: “I was gobsmacked when I saw this lemur meditating”. (Photo by Sebastien Degardin/Caters News)

In this September 30, 2017 photo, people perform “transvestite target practice” to protest the killings of transvestite prostitutes during the annual LGBQT march in Asuncion, Paraguay. Advocacy groups fear the stigma and attacks against the LGBQT community could get worse now that the country's education minister has banned classes about sexual diversity in schools and even volunteered to help burn all books related to the subject. (Photo by Jorge Saenz/AP Photo)

A costumed guest attends WonderCon Anaheim 2015 at Anaheim Convention Center on April 4, 2015 in Anaheim, California. (Photo by Araya Diaz/WireImage)

A tourist poses for a picture with the Sphinx at the Pyramids of Giza in Cairo, Egypt, on October 19, 2011. (Reuters/Jamal Saidi)

“Pivo”, Nissan's concept car is introduced at Nissan's Gallery on September 30, 2005 in Tokyo, Japan. “Pivo” is an electric car in which the direction of the cabin moves 180 degrees, therefore, when making a turn in a different direction, it simply needs to move the cabin without moving the car. (Photo by Koichi Kamoshida/Getty Images)

Tong Jieping, 44-year-old mentally disabled patient, is chained by his foot inside his room, in Qunxing village of Wangjiang county, Anhui province, China, July 14, 2015. Tong was diagnosed mentally ill when he was in his 20s. His parents, both in their 70s, could not afford the medical treatments so they had to lock him up in chains to prevent him from running away, according to Tong's family. (Photo by Reuters/Stringer)