To mark Halloween, 150 teens descended upon a swimming pool in Essex to help mobile network giffgaff recreate the famous Tomatina tomato fight... only this time, with blood and guts. Different takes #giffgaffguts. On October 18, 2013 in Dagenham, England. (Photo by Dave J. Hogan/Stringer for giffgaff)

A swimmer stops short of a red algae bloom at Sydney's Clovelly Beach on November 27, 2012, which closed some beaches for swimming including Bondi Beach for a period of time. While the red algae, known as Noctiluca scintillans or sea sparkle, has no toxic effects, people are still advised to avoid swimming in areas with discoloured water because the algae, which can be high in ammonia, can cause skin irritation. (Photo by William West/AFP Photo)

An animal rights protester demonstrates for the abolition of bull runs and bullfights, three days before the start of the famous running of the bulls San Fermin festival in Pamplona, northern Spain, July 4, 2015. (Photo by Eloy Alonso/Reuters)

This photo take on December 16, 2016 shows macaques monkeys playing on a motorbike in the grounds of a temple in Jaipur in the Indian state of Rajasthan. (Photo by Dominique Faget/AFP Photo)

A ring-tailed lemur sunbakes at Melbourne Zoo in Melbourne, Victoria, Australia on December 21 2016. (Photo by Julian Smith/EPA)

Two sheep fight in a competition in Zhangjiakou, Hebei province, China on August 1, 2017. (Photo by Reuters/China Stringer Network)

A baby Sumatran orangutan is bathed after arriving at a wildlife center at Ratchaburi province in Thailand September 13, 2017. (Photo by Kerek Wongsa/Reuters)

19 giant panda cubs, all born this year, meet the public at the Shenshuping Base of the China Conservation and Research Centre for the Giant Panda on October 13, 2017 in Ngawa Tibetan and Qiang Autonomous Prefecture, China. So far China Conservation and Research Centre for the Giant Panda has successfully bred 42 giant pandas this year. (Photo by VCG/VCG via Getty Images)