St Andrews University students skinny dip in the sea as May Day celebrations in St Andrews, Scotland on April 30, 2017. Hundreds of revellers ditched their clothes and bravely jumped into the bitterly cold North Sea. (Photo by Alamy Stock Photos)

A mahout leads an elephant calf to the river Tunga for bathing at the Sakrebailu Elephant Camp in Sakrebailu in the southern state of Karnataka, India, November 12, 2016. (Photo by Abhishek N. Chinnappa/Reuters)

Rita Ora performs an intimate gig at the newly relaunched Tezenis store at Oxford Circus crossing to celebrate her recent lingerie collaboration with Tezenis on December 13, 2016 in London, England (Photo by David M. Benett/Dave Benett/Getty Images for Tezenis)

A swimmer disguised as Superman dives into the lake during the 78th “Coupe de Noel” (Christmas cup) swimming race in the Lake Geneva, on December 18, 2016 in Geneva. More than 1800 participants took part in the event, a 12-meter-long swimming off the Geneva's bank in the 7 degrees Celsius cold water. (Photo by Fabrice Coffrini/AFP Photo)

Members of Hashid Shaabi or Popular Mobilization Forces (PMF) fire towards Islamic State militant positions in west of Mosul, Iraq, December 28, 2016. (Photo by Reuters/Stringer)

A girl marches alongside Salvadoran soldiers during the parade commemorating Independence Day in San Salvador, El Salvador September 15, 2016. (Photo by Jose Cabezas/Reuters)

A model presents a creation for the Amir Slama collection during Sao Paulo Fashion Week in Sao Paulo, Brazil, October 26, 2016. (Photo by Nacho Doce/Reuters)

Bella Hadid arrives at the amfAR Gala Cannes 2017 at Hotel du Cap-Eden-Roc on May 25, 2017 in Cap d'Antibes, France. (Photo by Michael Buckner/Variety/Rex Features/Shutterstock)