Caroline Wozniacki of Denmark serves in her match against Kaia Kanepi of Estonia during day four of the Toray Pan Pacific Open at Ariake Colosseum on September 28, 2011 in Tokyo, Japan. (Photo by Koji Watanabe/Getty Images)

Indonesian tourists take photos at the Marina Bay in Singapore May 14, 2015. When Singapore celebrated its 50th birthday as an independent country in August,the city state bore little resemblance to the tiny island nation that was expelled from Malaysia in 1965. Its physical stature has swollen by 20 percent thanks to one of the world's most aggressive land reclamation drives. (Photo by Edgar Su/Reuters)

An internally displaced Afghan girl holds a child at a refugee camp in Kabul, Afghanistan May 31, 2016. (Photo by Mohammad Ismail/Reuters)

An Afghan girl makes a pile of unbaked bricks near the road passing through the Shamali Plains, about 10 kilometers (6 miles), west of Bagram, Afghanistan, Wednesay April 9, 2003. Children assist parents in their job to supplement family income. (Photo by Gurinder Osan/AP Photo)

Lorella Boccia attends Giffoni Film Festival blue carpet on July 23, 2014 in Giffoni Valle Piana, Italy. (Photo by Maria Laura Antonelli/AGF/SIPA Press)

Harris & Ewing Inc. photographed people, events, and architecture, particularly in Washington, D.C., during the period 1905-1945. Photo: Tests of Curtiss Palne for Army, Single Control. Created by Harris & Ewing. Published in 1912.

The “Yama” (Pit) memorial is seen in the centre of Minsk May 5, 2015. The memorial is dedicated of the destruction of the Minsk ghetto during World War Two, when several hundred thousands of Jews were slaughtered. Belarus will mark Victory Day on May 9, the 70th anniversary of the Soviet Union's victory over Nazi Germany. (Photo by Vasily Fedosenko/Reuters)

A pilot inflates a hot air balloon while taking part in the 38th International Balloon Festival of Chateau-d'oex, Switzerland, 23 January 2016. The festival takes place from 23 to 31 January. (Photo by Vincent Vannay/EPA)