Brett Throckmorten of Barnes Bullets shows Logan Wingo how to sight down an electronic rifle in the trade booth area during the National Rifle Association's annual meeting in Nashville, Tennessee, April 11, 2015. (Photo by Harrison McClary/Reuters)

Russian servicemen drive a partially covered T-14 Armata tank along a street before a rehearsal for the Victory Day parade in Moscow, Russia, April 29, 2015. Russia will celebrate the 70th anniversary of the victory over Nazi Germany in World War Two on May 9. (Photo by Maxim Zmeyev/Reuters)

Vietnamese military personnel in traditional dress take part in a parade celebrating the 40th anniversary of the end of the Vietnam War which is also remembered as the fall of Saigon, in Ho Chi Minh City, Vietnam, Thursday, April 30, 2015. (Photo by Dita Alangkara/AP Photo)

An Israeli boy looks through the sight of a weapon during a display of Israeli Defense Forces (IDF) equipment and abilities at the West Bank settlement of Kiryat Arba, April 23, 2015, during celebrations for Israel's Independence Day, marking the 67th anniversary of the creation of the state. (Photo by Ronen Zvulun/Reuters)

French climber Alain Robert, also known as “Spiderman”, holds the flag of Nepal as he scales the Tour Montparnasse, a 210-metre (689 ft) building in central Paris, France April 28, 2015, to show support for the victims after the earthquake in Nepal. (Photo by Gonzalo Fuentes/Reuters)

Members of a music band rest before the procession of “Nossa Senhora da Boa Viagem”, in Constancia April 6, 2015. This benediction has been held annually for about 200 years. In the past, goods were transported by the Tagus river in small boats to Lisbon, 100 km south. The sailors, as the navigation was dangerous, blessed their boats every year during the festivity of “Nossa Senhora da Boa Viagem”. (Photo by Rafael Marchante/Reuters)

A child wades through the mud next to a grave inside the flooded cemetery in Los Loros town, April 7, 2015. The death toll from heavy rains and flooding that battered Chile last week has risen to 29, with another 150 still missing, according to authorities. (Photo by Ivan Alvarado/Reuters)

Thai officials inspect counterfeit watches before destroying them at Khlongluang Transportation Station in Pathumtani province, on the outskirts of Bangkok April 9, 2015. The counterfeit goods, which included piles of CDs, DVDs, handbags, clothes, brand name shoes, cell phones, caps, glasses, computers, cosmetics and watches are worth over 3.7 billion Thai baht ($ 115,790,901), according to local authorities. (Photo by Chaiwat Subprasom/Reuters)