People follow king penguins exploring their outdoor pen, during a so-called “penguin parade”, when the animals walk outside their enclosure and the visitors can walk behind them, at Zurich's Zoo in Zurich, Switzerland January 28, 2017. (Photo by Arnd Wiegmann/Reuters)

This photo taken on June 19, 2017 shows Indian yoga teacher Mahesh Yogiji attempting a world record for the longest yoga session in Ahmedabad, ahead of International Yoga Day on June 21. According to Guiness World Records, the longest yoga marathon undertaken by a man lasted 69 hours and was achieved by V Gunasekaran in Tamil Nadu in June 2016. (Photo by Sam Panthaky/AFP Photo)

A woman receives a bouquet made of vegetables and flowers, priced at 238RMB, from a delivery staff of a florist outside an office building on Valentine's Day in Beijing, China, February 14, 2017. (Photo by Jason Lee/Reuters)

A protester dressed as a clown holds an umbrella over a Swiss police officer on a motorbike during a May Day demonstration in Zurich, Switzerland on May 1, 2017. (Photo by Arnd Wiegmann/Reuters)

Mary, 8-months-old female orphan elephant, drinks milk at Winga Baw Elephant Conservation Camp during the ceremony to mark World Elephant Day at Bago Region, Myanmar, 12 August 2017. Winga Baw Elephant Conservation Camp, 34-hectare former timber camp for logs located in Bago Region, currently has 14 elephants and was opened for recreation for locals as well as for tourists. World Elephant Day is marked annually on 12 August. (Photo by Lynn Bo Bo/EPA/EFE)

Participants in costume take part in a walk for World Zombie Day 2017, on Place de la Republique in Paris, France, 07 October 2017. More than 50 cities worldwide participate in the worldwide horror festival in which revellers dress up as zombie-related characters. (Photo by Ian Langsdon/EPA/EFE)

A woman lies face-down on the floor where other race-goers are standing on 2017 Derby Day at Flemington Racecourse on November 4, 2017 in Melbourne, Australia. (Photo by Splash News and Pictures)

In 2013, the United Nations General Assembly officially designated November 19 as World Toilet Day, which is coordinated by UN-Water in collaboration with governments and partners. Here: An open-air toilet and a hot spring shower are seen in the middle of nowhere on the road to the Krafla geothermal power station and lava fields, near Reykjahlid and Lake Myvatn in northeastern Iceland, on August 19, 2012. (Photo by Mariana Suarez/AFP Photo)