A Nepalese Hindu devotee takes a holy bath as they mark the Mother's Day Festival at Matathirtha on the outskirts of Kathmandu on May 6, 2016. Nepalese Hindu devotees come from across the country to bathe, offer prayers and leave offerings at the Matathirtha Temple during the event, which honours mothers who have passed away. (Photo by Prakash Mathema/AFP Photo)

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)

A pet owner holds his guinea pig named Riec as Father Francisco bestows a blessing on the pet rodent during a feast day Mass in honor of Saint Anthony, the patron saint of animals, at the Saint Fernando church, in Mexico City, Saturday, January 17, 2015. Many people in Mexico bring their pets to churches to be blessed by the priest on this day. (Photo by Marco Ugarte/AP Photo)

Young people fight for fun with their pillows, during the International Pillow Fight Day at the Place des Grottes, in Geneva, Switzerland, Saturday, April 4, 2015. The annual International Pillow Fight Day takes place in hundreds of cities around the world. (Photo by Salvatore Di Nolfi/AP Photo/Keystone)

Ada Wood, 10, perches on one of Castlerigg’s 38 stones during the summer solstice at Castlerigg stone circle in Cumbria, Britain, on June 21, 2016. (Photo by Christopher Thomond/The Guardian)

A sniper of the French “Brigade d'Intervention” takes up his position at the top of the Arc de Triomphe during the annual Bastille Day military parade on the Champs-Elysees avenue in Paris on July 14, 2016. France holds annual Bastille Day military parade with troops from Australia and New Zealand as special guests among the 3,000 soldiers who will march up the Champs Elysees avenue. They will be accompanied by 200 vehicles with 85 aircraft flying overhead. (Photo by Stephane De Sakutin/AFP Photo)