On the first day of the Soviet withdrawal from Afghanistan in May 1988, an Afghan soldier hands a flag to a departing Soviet soldier in Kabul. "This was the first time journalists had full access to Kabul," Robert Nickelsberg says. It marked his first year covering Afghanistan. "It was a historical turning point for the Cold War and actually foreshadows the chaos that will descend on the country." Courtesy of Robert Nickelsberg/Getty Images hide caption
General Grant at City Point, created circa 1902 Library of Congress hide caption
"I struck upon this kind of crazy idea that I was going to go to New York and stop 10,000 people on the streets and take their portrait, and create kind of a photographic census of the city." Courtesy of St. Martin's Press hide caption
Jockeys ride wooden plows in the traditional sport of buffalo racing in Bali. Bram Paulussen/2015 National Geographic Photo Contest hide caption
A detail of Billy the Kid (left) in the original tintype. Courtesy of Kagins.com hide caption
Frazier's grandmother grew up in Braddock in the 1930s and '40s, when "it was prosperous and a melting pot," Frazier says. She took this photograph of her grandmother in 2002. Courtesy of artist LaToya Ruby Frazier hide caption
Pop icon and former Beatle Ringo Starr poses for the media in front of some of his photographs as he launches a book, Photograph, in London on Wednesday. Alastair Grant/AP hide caption
"Oh, look! There's a donkey in my living room!!!" was the photographer's Instagram caption. Adriana Zehbrauskas/Getty Images Instagram Grant Recipient 2015 hide caption
A photo from 1875 in Rio de Janeiro shows women street sellers called "quitandeiras," also known as "slaves who earn." A portion of the profits was returned to their masters. Marc Ferrez/Moreira Salles Institute hide caption
Tres hermanas- "Three Sisters", Cuajinicuilapa, Guerrero, Mexico, 1986. Tony Gleaton/Courtesy The Tony Gleaton Photographic Trust, All Rights Reserved hide caption
Gov. Bill Clinton shakes hands with the crowd as he arrives at a rally being held for him in Hartford, Conn., in March 1992. Jim Cole/AP hide caption
Second Place: Three gravel workmen look through a window at their workplace in Chittagong, Bangladesh. Dust and sand are everywhere. Faisal Azim/Courtesy of National Geographic Traveler Photo Contest hide caption
American socialite Rita Lydig in a 1905 photo. Gertrude Kasebier/Library of Congress hide caption
Ramona Martinez is under no illusion that this selfie is a work of art. Ramona Martinez/NPR hide caption
The hand-colored photo, titled "Reclining young lady," is of Stella Osarhiere Gbinigie when she was 16. Solomon Osagie Alonge/Franko Khoury/National Museum of African Art hide caption
"Winter is better. You can't get nothing on a summer day. You can't get no help in the summer. I don't have no place to stay, but I sleep out here sometimes on the streets. I try to make a little money to buy me a little something to eat because I don't like eating out of trash cans. That makes me sick." Joe Rubino/Close Up Baltimore hide caption
One of the princesses of Kabul. David Fox/Courtesy of Humans of Kabul hide caption
On the day that he announced his resignation, Richard Nixon ordered cottage cheese, pineapple slices and a glass of milk. Robert Knudsen/Nixon Library hide caption
The Weinfeld Family, 2009. Photographer Frederic Brenner, who took this photo, created This Place, an exhibit that features the work of 12 internationally acclaimed photographers in Israel and the West Bank. Frederic Brenner/Courtesy of Howard Greenberg Gallery hide caption
"Amanda and her Cousin Amy": Mary Ellen Mark photographed Amanda Marie Ellison, 9 (right), and Amy Minton Velasquez, 8, in Valdese, N.C., in 1990. Courtesy of Mary Ellen Mark Studio and Library hide caption
Instagram's latest update features curated photo collections and trending tags. Instagram hide caption