Japanese chorus girls appear to be drilling in military tactics atop their theater building as they perform salutes, June 30, 1937. The officer is from the Japanese regular army and says the girls display more rhythm in their drills than do the regular troops. (Photo by AP Photo)

North Korean military participate in the celebration of the 70th anniversary of the founding of the ruling Workers' Party of Korea, in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang on early October 11, 2015. (Photo by Reuters/KCNA)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

Labourers work at the installation site of Liquefied Petroleum Gas (LPG) pipeline on May Day or Labour Day in Chandigarh, India, May 1, 2015. (Photo by Ajay Verma/Reuters)

An instructor (C) adjusts the posture of students of flight attendant major during a training session at Anhui Foreign Languages University, in Hefei, Anhui province, China, May 25, 2015. (Photo by Reuters/China Daily)

In this photo provided by Jean Revillard, Solar Impulse 2, a plane powered by the sun's rays and piloted by Andre Borschberg, approaches Kalaeloa Airport near Honolulu, Friday, July 3, 2015. His 120-hour voyage from Nagoya, Japan broke the record for the world's longest nonstop solo flight, his team said. (Photo by Jean Revillard/Global Newsroom via AP Photo)

A brilliant sunset makes for a fun silhouette picture by jumping between sand bars at Shi Shi Beach on the Olympic Peninsula Friday July 17, 2015. (Photo by Bettina Hansen/The Seattle Times)

In this Sunday, March 29, 2015 photo, a young performer from the Parinacochas district of Ayacuhco dances in the Vencedores de Ayacucho dance festival, in the Acho bullring in Lima, Peru. The performers sang in the Quechua language, portraying the planting of corn and potatoes. From very young children to elderly people dressed as farmers, tigers, and foxes, as well as members of auto-defense groups, soldiers and police officers, to portray the violence that tore apart their families and communities. (Photo by Rodrigo Abd/AP Photo)