Topless activist Kaila J. walks through the rain following a “Free the Nipple” demonstration in Hampton Beach, New Hampshire August 23, 2015. (Photo by Brian Snyder/Reuters)

Women in lingerie touching each other. (Photo by BDLM/Getty Images)

Germany, Business couple making love under desk. (Photo by Roman Maerzinger/Getty Images)

Children feeding the birds in this Victorian Christmas greetings card. (Photo by Hulton Archive/Getty Images). Circa 1885

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/Getty Images)

Boys pan for gold on a riverside at Iga Barriere, 25 km (15 miles) from Bunia, in the resource-rich Ituri region of eastern Congo February 16, 2009. Ituri is one of many areas of the country to have experienced bitter ethnic conflict between rival tribes in recent years. Massacres have left tens of thousands dead. It is this fighting that led U.S. authorities to take the unprecedented step of naming Congo in section 1502 of the Dodd-Frank financial regulation act, which says U.S.-listed companies that source gold, tungsten, tantalum and tin from Congo or its neighbours must assure the U.S. stock exchange regulator that their business is not helping fund conflict. (Photo by Finbarr O'Reilly/Reuters)

(L-R) Singers Kelly Rowland, Beyonce and Michelle Williams perform during the Pepsi Super Bowl XLVII Halftime Show at the Mercedes-Benz Superdome on February 3, 2013 in New Orleans, Louisiana. (Photo by Ezra Shaw/Getty Images)

A man carrying an axe walks past a house marked with bullet holes in Gyallesu district after recent clashes between Shi'ites and the army in Zaria, Kaduna state, Nigeria, February 3, 2016. Sectarian tensions are rising in Nigeria's Muslim north, where hundreds of Shi'ites were killed in clashes with the army in the town of Zaria in December, according to Shi'ites and rights groups. Following the clashes, bulldozers sent by the state levelled Shi'ite shrines, a cemetery and offices in the deeply divided town. The region is already grappling with an insurgency waged by the jihadist Boko Haram group. (Photo by Afolabi Sotunde/Reuters)