Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

An Egyptian street vendor carries plastic dishes on a street decorated for the holy month of Ramadan in old Cairo, Egypt June 1, 2016. (Photo by Amr Abdallah Dalsh/Reuters)

Indian mourners perform a cremation on the roof of a building overlooking The Manikarnika Ghat in Varanasi on August 23, 2016. India's holy city of Varanasi has been forced to halt cremations along the banks of the sacred river Ganges as deadly floods from monsoon rains hit parts of the country, an official said. More than 100,000 people have been forced from their homes in recent days in northern Uttar Pradesh and neighbouring Bihar states as rain-swollen rivers burst their banks. (Photo by Sanjay Kanojia/AFP Photo)

Arlo Dela Cruz and Maica Nicerio-Dela Cruz on their wedding day with the Mayon volcano erupting in the background, in Daraga, Albay, Philippines on January 25, 2018. They were married earlier in the afternoon at Our Lady of the Gate Parish. After their wedding they walked out to Red Labuyo restaurant and the volcano started its eruption. The Mayon volcano continued to erupt Thursday. The airport in Legazpi is closed until at least 31 January 2018. (Photo by ZUMA Press/Alamy Stock Photo)

A dead wild boar is seen during a hunt in Castell'Azzara, Tuscany, central Italy, October 23, 2015. Extinct across much of the country by the end of the 1800s, the number of wild boar in Italy has almost doubled over the past decade and there are now about a million roaming the country, environmental and agricultural associations say. (Photo by Max Rossi/Reuters)

Greek actress Katerina Lehou, playing the role of High Priestess, lights a torch during the dress rehearsal for the Olympic flame lighting ceremony for the Rio 2016 Olympic Games at the site of ancient Olympia in Greece, April 20, 2016. Fire spurted from the concave mirror as a priestess, kneeling in her long, pleated dress before a ruined Greek temple, focused the blazing sun's rays on her metal torch. Come rain or shine on Thursday's official lighting ceremony, Rio de Janeiro has now secured its Olympic flame, which will burn in the main Olympic stadium throughout the Aug. 5-21 games. (Photo by Yannis Behrakis/Reuters)

In this January 7, 2017 photo, Judeley Hans Debel squats down to remove a boot from Tic Tac, holding out his prosthetic leg after his therapeutic riding lesson at the Chateaublond Equestrian Center in Petion-Ville, Haiti. Anne-Rose Schoen, who founded the equestrian center, said perhaps the most important thing about therapeutic riding is it makes youngsters happy in a country where disabled people face enormous challenges. (Photo by Dieu Nalio Chery/AP Photo)

In this picture taken on January 11, 2021, young gymnasts train at the Li Xiaoshuang Gymnastics School in Xiantao, Hubei province. This summer's delayed Tokyo Olympics, which are now due to start on July 23, 2021, will be the defining moment for Chinese gymnasts who have trained relentlessly since as young as age four in the pursuit of gold. (Photo by Nicolas Asfouri/AFP Photo)