The Lamb National takes place for the racegoers at Ascot Racecourse on April 2, 2017 in Ascot, England. (Photo by Alan Crowhurst/Getty Images)

Performers wearing traditional outfits demonstrate the Coopers' Dance on Marienplatz square on January 7, 2012 in Munich, Germany. The Coopers' Dance, known in German as the Schaefflertanz, is performed only every seven years and dates back to 1702. (Photo by Johannes Simon/Getty Images)

A leader “Rolli” of a yodel group “Schuppel” runs in the snow in front of a farmstead during the “Silvesterchlausen” in the early morning in Urnaesch in the Swiss canton Appenzell Ausserroden on January 13, 2017. (Photo by Michael Buholzer/AFP Photo)

Durga Kami, 68, who is studying tenth grade at Shree Kala Bhairab Higher Secondary School, walks with his classmate Sagar Thapa, 14, as they head to school in Syangja, Nepal, June 5, 2016. (Photo by Navesh Chitrakar/Reuters)

Ten day old male Gorilla “Fataki” clings to his mother “Frala” during his media debut at Taronga Zoo June 4, 2003 in Sydney, Australia. Fataki was born on May 24, 2003 and was the fourth Gorilla to be born at Taronga Zoo since the opening of the Gorilla Forest in 1997. (Photo by Chris McGrath/Getty Images)

A six-day-old hippopotamus is pictured next to his mother, Kara, aged 21, on September 12, 2012 at “Planet sauvage” (“Wild planet”) Zoo in Port-Saint-Pere, western France. The birth, a rare event for this species in captivity, occured on September 7, 2012 in the Zoo. (Photo by Frank Perry/AFP Photo)

The tempestuous stellar nursery called the Carina Nebula, located 7,500 light-years away from Earth in the southern constellation Carina. (Photo by Reuters/NASA)

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)