Dr. P.A. Smithe was sent by the American Red Cross as a doctor and surgeon to work at a hospital in Vienna. He sailed to Europe in December 1915 and returned home in August 1916, according to his daughter, who donated his images to the National World War I Museum. Photo: Turkish army, including cavalry, infantry and artillery. (Photo by Dr. P.A. Smithe/National World War I Museum, Kansas City, Mo.)

People clash with Venezuelan National Guards as they try to cross the border to Colombia over the Francisco de Paula Santander international bridge in Urena, Venezuela December 18, 2016. (Photo by Carlos Eduardo Ramirez/Reuters)

This 1950s photo provided by the Estate of Vivian Maier and John Maloof Collection shows Maier in a self-portrait as she looks into a storefront wearing a hat in New York. New research about Maier shows the enigmatic Chicago nanny was obsessive about honing her skills as a photographer starting in 1950. (Photo by Vivian Maier/Estate of Vivian Maier and John Maloof Collection via AP Photo)

In this January 27, 2020 photo, Jessica Hahn-Chaplin applies make up before a rehearsal of the Paraiso de Tuiuti samba school in Rio de Janeiro, Brazil. Hahn-Chaplin dances samba annually in Bath, England. (Photo by Silvia Izquierdo/AP Photo)

Commuters by with the buildings of the banking district in background in Frankfurt, Germany, Thursday, February 6, 2020. (Photo by Michael Probst/AP Photo)

Protesters use fireworks against riot police during clashes in the Athens neighborhood of Exarchia, a haven for extreme leftists and anarchists, Thursday, December 6, 2018. New protest marches were underway in Greece Thursday evening on the 10th anniversary of the fatal police shooting of a teenager, hours after violent initial demonstrations where masked youths attacked police with firebombs and stones. (Photo by Yorgos Karahalis/AP Photo)

A Palestinian throws snow at his wife during a snow storm in West Bank old city of Hebron, January 26, 2016. (Photo by Mussa Qawasma/Reuters)

Truffle hunter Carlo Marenda pets his dog Buc as they search for white truffles through the Langhe Countryside in Roddi, near Alba, north-western Italy, on November 8, 2020. Despite new measures to stop the spread of the Covid-19, truffles hunters are allowed to search in the countryside in Italy. (Photo by Marco Bertorello/AFP Photo)