A German Air Force Officer sits astride a dead boar outside a house where he is stationed near the Western Front, in this 1918 handout picture. This picture is part of a previously unpublished set of World War One (WWI) images from a private collection. The pictures offer an unusual view of varied and contrasting aspects of the conflict, from high tech artillery to mobile pigeon lofts, and from officers partying in their headquarters to the grim reality of life and death in the trenches. The year 2014 marks the centenary of the start of the war. (Photo by Reuters/Archive of Modern Conflict London)

“Sidney D. Gamble (July 12, 1890 – 1968) was born in Cincinnati, Ohio, to David Berry and Mary Huggins Gamble; grandson of James Gamble, who, with William Procter, founded Procter & Gamble in 1837. in 1912 he graduated magna cum laude from Princeton University with a Bachelor of Literature degree and was elected to Phi Beta Kappa. He visited China for four extended periods, 1908, 1917–1919, 1924–27, and 1931–1932, doing Christian social work for the Y.M.C.A and conducting social surveys. He is now best known for his remarkable and extensive photographs of Peking and North China.” – Wikipedia. (Photo by Sidney David Gamble via Duke University Libraries)

Photo: Hillcoat Riding Fu Tu. China, An Xian, 1917-1919. P.S. All photos are available in high resolution.

In this photograph taken on June 28, 2015, a hiker in Hong Kong takes a picture of the city from a walking trail. The southern Chinese territory is crisscrossed by more than 180 miles of designated hiking trails. (Photo by Alex Ogle/AFP Photo)

Men ride a motorcycle in front of destroyed houses after Hurricane Matthew passes Jeremie, Haiti, October 7, 2016. (Photo by Carlos Garcia Rawlins/Reuters)

Indonesian residents look at the Mount Sinabung volcano as it spews volcanic ash near the Tiga Pancur village in Karo, North Sumatra on August 3, 2016. Volcanic eruptions in Indonesia in recent days have forced the closure of two airports and disrupted some flights to the holiday island of Bali, officials said August 3. Mount Sinabung, a volcano on the western island of Sumatra which has been rumbling for some time, also erupted violently on August 2, although its ash clouds did not disrupt any flights. (Photo by Y.T. Haryono/AFP Photo)

Elementary school children play outside their classrooms as mount Sinabung volcano spews thick volcanic ash in the background on February 10, 2017 in Karo, Indonesia. Mount Sinabung is one of the most active volcanoes in Indonesia and last erupted in May 2016, killing seven people. (Photo by Albert Damanik/Barcroft Images)

Dancers from the British theater company Motionhouse perform a show with excavators entitled “Traction” on the Prado beach in Marseille, France, on May 10, 2013. (Photo by Boris Horvat/AFP Photo)

Attendees look at Volkswagen's BUDD-e, a long distance electric vehicle, displayed during a press event at CES 2016 at The Chelsea at The Cosmopolitan of Las Vegas on January 5, 2016 in Las Vegas, Nevada. CES, the world's largest annual consumer technology trade show, runs from January 6-9 and is expected to feature 3,600 exhibitors showing off their latest products and services to more than 150,000 attendees. (Photo by David Becker/Getty Images)