A participant falls on vintage skis during a traditional historical ski race in the northern Bohemian town of Smrzovka February 21, 2015. (Photo by David W. Cerny/Reuters)

These beautiful shots may look like works of modern art – but they are actually close-ups of chemical reactions. The works were snapped with the help of a group of scientists from the University of Science and Technology of China (USTC) in Anhui, China. Here: Zinc reacting with lead nitrate in a soft gel to form lead crystals. (Photo by Yan Liang/Caters News)

A Hong Kong Vegetarian Society activists lies on a giant plate alongside oversized peas, carrots and cutlery during a protest rally in the tourist district of Tsim Sha Tsui, Hong Kong, China, 23 December 2015. The activists urged passers-by to extend the holiday spirit to animals and to give thoughts to the cruelty inflicted on animals in meat productions. (Photo by Jerome Favre/EPA)

Fighters of the pro-government Popular Resistance Committees militia carry a cannon as they transport it in parts to Yemen's southwestern war-torn city of Taiz December 26, 2015. (Photo by Reuters/Stringer)

North Korean leader Kim Jong Un (front) stands on the conning tower of a submarine during his inspection of the Korean People's Army (KPA) Naval Unit 167 in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang June 16, 2014. (Photo by Reuters/KCNA)

High-wire artist Kane Petersen successfully walks a tightrope 300 metres above the ground at Eureka Skydeck on September 16, 2015 in Melbourne, Australia. The walk was the highest tightrope walk ever attempted in the Southern Hemisphere. The stunt is to mark the arrival of the film “The Walk” to Australian cinemas in October. The stunt saw Kane mimic the film's French high-wire artist Philippe Petit, who successfully walked between the twin towers of the World Trade Center in 1974. (Photo by Scott Barbour/Getty Images)

A model presents a creation at the Moschino fashion show during Milan Fashion Week Spring/Summer 2017 in Milan, Italy, September 22, 2016. (Photo by Alessandro Garofalo/Reuters)

Students from St Andrews University are covered in foam as they take part in the traditional “Raisin Weekend” in the Lower College Lawn, at St Andrews in Scotland, Britain October 17, 2016. The weekend, which begins on Sunday, involves rituals for new students, culminating in a foam fight on Monday morning. (Photo by Russell Cheyne/Reuters)