An artist draws a tattoo on a woman's arm during a tattoo convention in Ljubljana April 18, 2015. (Photo by Srdjan Zivulovic/Reuters)

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

Businesswoman and vendor Sonia Maria Paypay sells clothing at a stand at the commercial zone of Gamarra in Lima, April 16, 2015. (Photo by Mariana Bazo/Reuters)

A woman plays with a kitten inside of a line house in downtown Shanghai April 12, 2015. (Photo by Carlos Barria/Reuters)

Dogs perform during “Stars and starlets”, a new programme, at the National Circus in the Ukrainian capital of Kiev April 30, 2015. (Photo by Gleb Garanich/Reuters)

A man smokes marijuana during a demonstration in support of the legalization of marijuana in Medellin, May 2, 2015. (Photo by Fredy Builes/Reuters)

Sumo wrestlers compete during the “Honozumo” ceremonial sumo tournament at the Yasukuni Shrine in Tokyo April 3, 2015. (Photo by Thomas Peter/Reuters)

A woman is tattooed during the Great British Tattoo Show in Alexandra Palace in north London, Britain May 23, 2015. (Photo by Neil Hall/Reuters)