Tank crew standing in front of M-4 tank, Ft. Knox, Kentucky, June, 1942. (Alfred Palmer/OWI/LOC)

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)

Kaw-Claa, a Tlingit native woman in full potlatch dancing costume, 1906. (Photo by Case & Draper/Buyenlarge/Getty Images)

Runner English Gardner poses for a portrait at the U.S. Olympic Committee Media Summit in Beverly Hills, Los Angeles, California March 8, 2016. “My musical inspiration when I'm training is usually a lot of upbeat music”, said Gardner. (Photo by Lucy Nicholson/Reuters)

Sun Model students pose for a photo during a training session at the school on March 31, 2014 in Phnom Penh, Cambodia. Having started in August 2010 with only three models, the Sun Model Agency and School is starting to make an impact in the fashion industry in Cambodia. (Photo by Omar Havana/Getty Images)

These poignant portraits look to shine awareness on the plight of some of the world’s most endangered ecosystems and species of wildlife. The images combine animals, art and celebrity, with Asia's top models posing with the likes of rhinos, giraffes, leopards and marine life. Here: Mikki Yao with an Asian Elephant. (Photo by Sean Lee-Davies/Caters News)

Enthusiasts gather for the Model Rail Scotland exhibition on February 24, 2012 in Glasgow, Scotland. (Photo by Jeff J. Mitchell/Getty Images)