A young girls holds a ballot during the Greek referendum in Athens on July 5, 2015. Greek voters headed to the polls today to vote in a historic, tightly fought referendum on whether to accept worsening austerity in exchange for more bailout funds, in a gamble that could see it crash out of the euro. (Photo by Aris Messinis/AFP Photo)

Hundreds of Nigerians celebrate at an intersection in the flashpoint northern city of Kaduna on March 31, 2015 the victory of main opposition All Progressives Congress (APC) presidential candidate Mohammadu Buhari. (Photo by Nichole Sobecki/AFP Photo)

A Free Syrian Army (FSA) fighter reacts as he mourns near the body of his brother, who was an FSA fighter and died during an offensive against Islamic State fighters to take control of Qabasin town, on the outskirts of the northern Syrian town of al-Bab, Syria January 10, 2017. (Photo by Khalil Ashawi/Reuters)

Silver medalist Vivian Jepkemoi Cheruiyot of Kenya and gold medalist Almaz Ayana (R) of Ethiopia during the medal ceremony for the women's 10000m final of the Rio 2016 Olympic Games Athletics, Track and Field events at the Olympic Stadium in Rio de Janeiro, Brazil, 12 August 2016. (Photo by Sergei Ilnitsky/EPA)

Chinelos (traditional costumed dancers) perform in front of San Andres Ocotlan church as part of continuing festivities to welcome the new year in Calimaya, Mexico on January 4, 2016. (Photo by Arturo Hernandez/Demotix/Corbis)

Chinese hostesses, who serve the delegates of the Chinese People's Political Consultative Conference and National People's Congress, have souvenir photos taken in front of the Great Hall of the People during sessions of the CPPCC and NPC held in Beijing, China Tuesday, March 4, 2014. (Photo by Andy Wong/AP Photo)

Number 10. BELL H-13 SIOUX was a two-bladed, single engine, light helicopter built by Bell Helicopter. Westland Aircraft manufactured the Sioux under license for the British military as the Sioux AH.1 and HT. In 1947, the United States Air Force ordered the improved Bell Model 47A. Most were designated YR-13 and three winterized versions were designated YR-13A. The United States Army first ordered Bell 47s in 1948 under the designation H-13. These would later receive the name Sioux. The Bell-built H-13 B is seen airborne in this April 29, 1951 photo. The helicopter is equipped with a 173 horsepower engine, cruises at 85 miles per hour, climbs 900 feet in a minute and has a service ceiling of 11,500 feet. (Photo by AP Photo)

A man dressed in leaves and animals of the forest, the Redeemer on his shoulder, holding the Olympic torch and wearing Olympic rings glasses walks along Copacabana Beach, Rio de Janeiro, Brazil, 31 July 2016. The 2016 Olympic Games start on 05 August. (Photo by Barbara Walton/EPA)