National Guardsmen are put through riot training in Boston's Commonwealth Armory on Friday, October 18, 1974. Massachusetts Gov. Francis W. Sargent called up the guard to quell school violence, but the city has been relatively calm and the guard has remained in the armories. (Photo by JWG/AP Photo)

A dog is kept at a pen at the newly opened Central Zoo in Pyongyang, North Korea, Tuesday, August 23, 2016. One of the most popular attractions at the zoo might come as a surprise to foreign visitors. Just across the way from the hippopotamus pen and the reptile house, dozens of varieties of dogs, including schnauzers, German shepherds, Shih Tzus and Saint Bernards – are on display in the “dog pavilion”. (Photo by Dita Alangkara/AP Photo)

“As a photographer, peregrinator and naturalist, I have been searching for the ultimate unworldly world. I've always been drawn to unusual travel destinations. For me, to lose myself in a different culture is a great way to find balance in my life...”. – Li Xinzhao. (Photo by Li Xinzhao)

Linda Evangelista, Naomi Campbell, Polly Mellon, and Christy Turlington, The Fashion Group International's 6th Annual “Night of 100 Stars” at the The Plaza Hotel in New York City, New York on October 29, 1989. (Photo by Ron Galella/WireImage)

A tourist poses for a picture with the Sphinx at the Pyramids of Giza in Cairo, Egypt, on October 19, 2011. (Reuters/Jamal Saidi)

British glamour model and actress Sabrina (born Norma Ann Sykes, 1936-2016), during a press conference at Park Lane House in London on June 24, 1955. (Photo by ANL/Rex Features/Shutterstock)

A monkey jumps from a branch at Yangon Zoological Gardens in Yangon, Myanmar, 06 April 2016. Yangon Zoological Gardens (Yangon Zoo) is the oldest and second largest zoo in Myanmar. (Photo by Lynn Bo Bo/EPA)

A woman offers prayers by a road as a rickshaw puller transports passengers in Kolkata October 28, 2014. (Photo by Rupak De Chowdhuri/Reuters)