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)

Man prepares wigs as he waits for customers in downtown Johannesburg, on August 5, 2014. Some estimates put Africa's dry hair industry at as much as $6 billion a year; Nigerian singer Muma Gee recently boasted that she spends 500,000 naira ($3,100) on a single hair piece made of 11 sets of human hair. (Photo by Siphiwe Sibeko/Reuters)

Many powerful photographs have been made in the aftermath of the devastating collapse of a garment factory on the outskirts of Dhaka, Bangladesh. But one photo, by Bangladeshi photographer Taslima Akhter, has emerged as the most heart wrenching, capturing an entire country’s grief in a single image... Photo: Two victims amid the rubble of a garment factory building collapse in Savar, near Dhaka, Bangladesh, April 25, 2013. (Photo by Taslima Akhter)

Professional dog walker Jon Lovette of Jonny Walkers walks with dogs at Crissy Field on October 19, 2011 in San Francisco, California.

Giant panda Mei Xiang discovers a birthday cake meant for her cub Bei Bei (NP) who turns one at the Smithsonian National Zoo in Washington, DC on August 20, 2016. (Photo by Linda Davidson/The Washington Post)

Zamora, 55, self-employed, poses for a photograph in front of the Cuban and U.S. flags after buying a pineapple in Havana, March 25, 2016. Regarding Obama's historic visit to the island, Zamora said “It's good for the Cubans that he came and re-established relationships between the two countries”. (Photo by Ueslei Marcelino/Reuters)

“The Family of Man” opened at The Museum of Modern Art in January 1955 and was curated by Edward Steichen. It was groundbreaking in its scope – 503 images by 273 photographers from 68 countries – as well as in the numbers of people who experienced it on its tour through 88 venues in 37 countries. The touring exhibit drew over 9 million people and the accompanying catalog sold over 2.5 million copies. Here: “Coney Island, New York”, by American photographer Garry Winogrand, circa 1952. (Photo by Garry Winogrand)

“Photographer Seth Casteel has definitely taken animal photography to new heights – or depths – with his hilarious photos of dogs chasing balls underwater. Casteel, who, naturally, has two dogs of his own (a mini Labradoodle and a Norwich terrier), said that he's drawn to underwater dog photography because the photos show a side of dogs that people may have never seen before”.

Photo: Seth Casteel Underwater Dog Pictures (Photo by Seth Casteel)