Tourists walk above a tea plantation in Enshi, Hubei province, December 27, 2015. (Photo by Reuters/Stringer)

New parents Chrissy Teigen and John Legend are seen leaving Khloe Kardashian's 32nd birthday party held at Dave and Buster's in Hollywood, California on June 28, 2016. (Photo by Splash News)

Tomomi Ota visits a local shrine with her humanoid robot Pepper in Tokyo, Japan, 26 June 2016. Reaching 120cm in height and 28 kilograms in weight, Pepper does not enter in the category of portable robot. But those characteristics dont stop Tomomi Ota to take Pepper in a cart to stroll in her neighborhood, go shopping or even take the subway... (Photo by Franck Robichon/EPA)

A 1949 Porsche 356 SL is displayed during the Porsche Rennsport Reunion V at Laguna Seca Raceway near Salinas, California, September 26, 2015. The three-day reunion is billed by organizers as the world's largest gathering of Porsche racecars, renowned drivers, and Porsche collector cars. (Photo by Michael Fiala/Reuters)

A Tibetan rider fires his weapon as he perfoms his riding skills at the Qinghai Yushu Horse Racing Festival on July 27, 2007 in Yushu County of Yushu Tibetan Autonomous Prefecture, Qinghai Province, northwest China. The Horse Racing Festival of Tibetan nomads in Yushu Prefecture falls in late July and early August on the Tibetan calendar. During the festival, various equestrian skills will be performed along with singing, dancing and costume shows. (Photo by China Photos/Getty Images)

A woman buys bread at a bakery in Cairo, January 8, 2015. The successful roll-out so far of a new “smart card” system to distribute subsidised bread has been a major achievement for Egypt's government, saving money while earning praise from families who no longer have to wake early to fight for loaves. (Photo by Mohamed Abd El Ghany/Reuters)

Hungarian pilot and European champion Zoltan Veres flies under the oldest Hungarian bridge, the “Lanchid” (Chain Bridge) with his “MXS” type plane on May 1, 2014 during a Red Bull flying and car show around the Danube River of Budapest downtown. (Photo by Attila Kisbenedek/AFP Photo)

At the beginning of the 20th century, Edward S. Curtis set out to document what he saw as a disappearing race: the Native American. From 1907 to 1930, Curtis took more than 2,000 photos of 80 tribes stretching from the Great Plains to the Pacific Northwest and Alaska. He then published and sold these photos, along with narrative text, in 20 volumes of work known as “The North American Indian”. It is one of the most significant collections of its kind, “probably the most important photographic document of its age and its topic,” said Jeffrey Garrett, associate university librarian for Special Libraries at Northwestern University. (Photo by Edward S. Curtis)