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)

A Guarani Indian woman jokes with her son in the village of Pyau at Jaragua district, in Sao Paulo April 27, 2015. The National Indian Foundation (FUNAI) has recognised 521 hectares of this area as indigenous territory, making it the smallest indigenous reserve in Brazil. Members of the Guarani community have now established a new village outside the demarcation and are being threatened with an eviction through a court order. (Photo by Nacho Doce/Reuters)

The world-famous sprinter Usain Bolt, 30, took a break from the track to celebrate Carnival as revellers doused each other with paint in Trinidad and Tobago on February 26, 2017. (Photo by David Wears/Splash News and Pictures)

Sarah Bui poses for photographer, Brian Le around blossoming cherry trees, near the Tidal Basin on Thursday March 23, 2017 in Washington, DC. (Photo by Matt McClain/The Washington Post)

Soniya, 6, whose family moved to Islamabad from Pakistan's Khyber-Pakhtunkhwa province to look for work, stands outside their house on the outskirts of Islamabad January 1, 2015. (Photo by Zohra Bensemra/Reuters)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, run at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. Boko Haram says it is building an Islamic state that will revive the glory days of northern Nigeria's medieval Muslim empires, but for those in its territory life is a litany of killings, kidnappings, hunger and economic collapse. (Photo by Afolabi Sotunde/Reuters)

A little boy shouts “Earthquake!” during a shouting contest, part of the annual evacuation drill on the National Disaster Prevention Day on September 1, 1986. The contest was aimed at teaching youngsters the importance of telling neighbors quickly and loudly of a disaster when it hits. The drill is annually conducted through out the country on the day marking the anniversary of the Great Kanto Earthquake that hit the Japanese capital and its vicinity on September 1, 1923, killing more than 104,000 people. (Photo by Sadayuki Mikami/AP Photo)