A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

People on motor bikes celebrate American President Barack Obama's visit to Kenya by holding up a photo, center top, of the president and First Lady Michelle Obama in Kisumu, Kenya, Saturday, July 25, 2015. President Barack Obama heralded Africa as a continent “on the move” Saturday as he opened a U.S.-sponsored business summit in Kenya, the East African nation where he has deep family ties. (Photo by AP Photo)

Models parade at the end of Moschino's Autumn/Winter 2017 women's collection during Milan Fashion Week in Milan, Italy, February 23, 2017. (Photo by Stefano Rellandini/Reuters)

“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)

An unidentified guest wears a hat with a lion at the Grand Palais which is transformed into a Chanel airport before German designer Karl Lagerfeld's Spring/Summer 2016 women's ready-to-wear collection for French fashion house Chanel during Fashion Week in Paris, France, October 6, 2015. (Photo by Benoit Tessier/Reuters)

Indian folk dancers display ornaments during a break while participating in the first night of Navratri in Gandhinagar, some 30 km from Ahmedabad, on October 13, 2015. Navratri festivities, or Dance Festival of Nine Nights, takes place between October 13-21. (Photo by Sam Panthaky/AFP Photo)

Crowds watch surfers as the first big swell of the year arrives in Nazaré, Portugal on October 28, 2015. (Photo by Pedro Miranda/Demotix/Corbis)