A glass is checked at the table for China's top leaders before the start of a reception to celebrate National Day at the Great Hall of the People in Beijing, China September 30, 2016. China celebrates its National Day on October 1. (Photo by Damir Sagolj/Reuters)

Rebecca Smith poses for a photograph during winter solstice with her Irish Wolfhound dog called Amazing Grace at the 5000 year old stone age tomb of Newgrange (not in view) in the Boyne Valley at sunrise in Newgrange, Ireland, December 21, 2016. (Photo by Clodagh Kilcoyne/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)

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 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)