A protester gestures after he saw a dead protester in Kampala, Uganda February 15, 2016. At least one person has been killed in Uganda's capital Kampala as police clashed with opposition supporters after briefly detaining a top presidential candidate twice as he tried to hold campaign rallies days before a general election. Several people were wounded in the clashes as police fired bullets and tear gas while opposition supporters hurled rocks and erected street barricades in the capital's Wandegeya suburb, witnesses said according to a Reuters news agency report. (Photo by Goran Tomasevic/Reuters)

An image produced by the Hubble telescope of the perfectly “edge-on” galaxy, or NGC 4013, March 1, 2001. This new Hubble picture reveals, with great detail, huge clouds of dust and gas extending along, as well as far above, the galaxy's main disk. NGC 4013 is a spiral galaxy, similar to the Milky Way, lying some 55 million light-years from Earth in the direction of the constellation Ursa Major. Viewed face-on, it would look like a nearly circular pinwheel, but NGC 4013 happens to be seen edge-on from our vantage point. Even at 55 million light-years, the galaxy is larger than Hubble's field of view, and the image shows only a little more than half of the object, albeit with unprecedented detail. (Photo Courtesy of NASA/Newsmakers)

A man wearing a Guy Fawkes mask enjoys a ride on a 350-meter (1148 feet) long water slide during 2015 City Silde Festa in central Seoul, South Korea, July 19, 2015. A 350 meter-long waterslide has been installed in downtown of Seoul, the longest waterslide to be recorded in Korea, according to local media. (Photo by Kim Hong-Ji/Reuters)

Ethnic Miao men wearing traditional masks smear dust on a woman's face to wish her good luck during local celebration event for Lunar New Year in Liuzhou, Guangxi Zhuang Autonomous Region, China, February 16, 2016. (Photo by Reuters/Stringer)

Penitent Jerry Mazon, 9, wears his “Morions” mask while playing with his baby brother during Holy Week celebrations in Mogpog, Marinduque in central Philippines March 22, 2016. (Photo by Erik De Castro/Reuters)

Venezuela: An anti-government protester wearing a Guy Fawkes mask throws a molotov cocktail at the Bolivarian National Police during clashes in Caracas, Venezuela, Thursday, April 17, 2014. Opposition protesters have been demonstrating against high crime, high inflation and shortages of basic goods since mid-February. (Photo by Ramon Espinosa/AP Photo)

Participants pass an egg using their mouths during a religious ritual as they play the role of traditional fighters in a parade during the Popo (Mask) Carnival of Bonoua, in the east of Abidjan, April 18, 2015. The carnival has its origins in the changes that Aboure youths in Bonoua introduced to the annual festival of yams. (Photo by Luc Gnago/Reuters)