People at a Czech Stop look at a cloud of smoke rising from the explosion in West, Texas, April 17, 2013. (Photo by Andy Bartee via Dallas Morning News/MCT)

Women wearing traditional hats, known as a non la, sell fruits in Hoi An, Vietnam April 4, 2016. The non la hats are made of readily available materials such as palm leaves, tree bark and bamboo and are visible everywhere in the city, a UNESCO World Heritage site. Hoi An's history as a busy trading port is evident throughout its architecture, a mix of eras and styles, with traditional wooden Vietnamese houses, Chinese temples and French colonial buildings. (Photo by Jorge Silva/Reuters)

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/Getty Images)

Children feeding the birds in this Victorian Christmas greetings card. (Photo by Hulton Archive/Getty Images). Circa 1885

(L-R) Singers Kelly Rowland, Beyonce and Michelle Williams perform during the Pepsi Super Bowl XLVII Halftime Show at the Mercedes-Benz Superdome on February 3, 2013 in New Orleans, Louisiana. (Photo by Ezra Shaw/Getty Images)

A baby bush-baby in a set of scales at London Zoo shortly after birth. (Photo by Fox Photos/Getty Images). 10th August 1938

A view of the screen of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. (Photo by David Ryder/Reuters)

Players perform during a game at the first Bubble Soccer tournament in Hitzkirch, near Lucerne, Switzerland, June 27, 2015. Bubble Soccer, also known as Zorb Soccer, is becoming increasingly popular around the world. The game is a recreation of playing soccer whilst encased in an inflated zorb which covers the players upper-body and head. (Photo by Urs Flueeler/EPA)