Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)

A red fox sits in front of a Eurofighter Typhoon combat jet on the grounds of the 2014 ILA Berlin Air Show, in Selchow near Schoenefeld, Germany, Thursday, May 15, 2014. The International Aviation and Aerospace Exhibition ILA will take place from May 20 until May 25, 2014. (Photo by Patrick Pleul/AP Photo/DPA)

Two friends take a quick selfie during the Grand National Festival at Aintree Racecourse on April 6, 2017 in Liverpool, England. (Photo by WENN)

A selection of winning images from the Life in Another Light photo contest 2020, from Kolari Vision. Here: Lights and Shadows in the Dolomites, in the landscape infrared category. (Photo by Tomasz Grzyb/Kolari Vision)

Travel concept: commercial airplane flying with beautiful charming stewardess on September 12, 2019. (Photo by Volodymyr Tverdokhlib/Alamy Stock Photo)

A girl looks with comic disgust at a guy who falls asleep with a bottle of beer at a party; her friend laughs. (Photo by Edward Corbett/Rex Features/Shutterstock)

A sledding dog is covered in ice after spending the night in the open air with his musher at the polar base of Val-Cenis, as they ready for the next stage of the 12th edition of “La Grande Odyssee” sledding race across the Alps on January 17, 2016 in Val Cenis Lanslevillard. (Photo by Jean-Philippe Ksiazek/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)