The 2016 Greenwich Village Halloween parade, October 31, 2016 in the Manhattan borough of New York City. (Photo by Anthony Causi)

“T'antawawas” (children's bread) are displayed in a popular market to commemorate All Saints Day in La Paz, October 30, 2016. (Photo by David Mercado/Reuters)

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)

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 graffiti, portraying a woman, is seen in Medellin, Colombia on November 19, 2017. Mural graffitis from different artists, street art can be seen in almost every city on Earth, but street arts raw power and potential for change was felt by me most intensively in Medellins Comuna 13, previously one of Colombias most dangerous neighbourhoods, in fact Communa 13 was constant battleground between gangs, narcos, paramilitaries and the government, but today you would hardly recognise it. (Photo by Juancho Torres/Anadolu Agency/Getty Images)

A woman walks with a squirrel on her shoulder at Maeklong market at the outskirts of Bangkok, Thailand September 20, 2016. (Photo by Jorge Silva/Reuters)

A visitor tries out Lenovo augmented reality glasses with the Star Wars Jedi Challenges during the Mobile World Congress in Barcelona, Spain, February 26, 2018. The Mobile World Congress, the world' s biggest mobile fair, is held in Barcelona from February 26 to March 1. (Photo by Yves Herman/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)