A visitor holds an Israeli-made rifle during the 8th International Land and Naval Defense system exhibition, in New Delhi, India, on February 6, 2014. (Photo by Anindito Mukherjee/Reuters)

Dancers pose after performing “El Macho Raton”, “El Toro Huaco” and “El Gueguense” traditional dances during San Sebastian festivity in Diriamba, province of Carazo, some 50 km south of Managua on January 19, 2016. Devotees of Saint Sebastian dance in traditional costumes between the cities of Diriamba and Dolores, which are some three kilometers away. (Photo by Inti Ocon/AFP Photo)

“Woman with Umbrella in Rain” by Raimund von Stillfried. Artist: Kusakabe Kimbei (Japanese, 1841–1934), 1870s. Commercial photography studios in Meiji-era Japan were renowned for the subtlety and refinement of their coloring techniques. This hand-tinted image of a young woman caught in a heavy rainstorm achieved its naturalistic effect by knitting together multiple strands of artifice: the greenery in the foreground was a studio prop; the flaps of the kimono were suspended by thin wires to create the impression of a strong wind; and long, diagonal marks were made on the negative to suggest streaks of rain. (Photo courtesy of The Metropolitan Museum of Art)

A storm whips through a tented area occupied by Nepalese earthquake survivors as a mother grabs her infant child and runs to find shelter in Kathmandu, Nepal 23 May 2015. Nepalese, who lost their homes in earthquake and fear aftershocks, have been living in temporary shelter in open ground which they had to flee because of the heavy rain and powerful wind. (Photo by Narendra Shrestha/EPA)

In this photograph taken on June 28, 2015, a hiker in Hong Kong takes a picture of the city from a walking trail. The southern Chinese territory is crisscrossed by more than 180 miles of designated hiking trails. (Photo by Alex Ogle/AFP Photo)

Participants take part in the annual Great Spitalfields Pancake Race in aid of London's Air Ambulance in London, Britain February 9, 2016. (Photo by Stefan Wermuth/Reuters)

People look at a tanker after it fell into a caved-in area on a road in Xi'an, Shaanxi province, July 27, 2013. No casualty was reported in the accident, according to local media. (Photo by Reuters/Stringer)

“Show us our butts! Mucawana tribe – Angola. In Soba village, the Muhacaona (Mucawana) tribe, perhaps the best place i have visited. They use cow dung and fat to make this so nice haircut, and love the beads. They asked me to make pictures of their backs... and butts to see on the camera screen if everything was perfect!”. (Photo and comments by Eric Lafforgue)