Two F-15E Strike Eagles wait to receive fuel from a KC-135R Stratotanker during exercise Red Flag 15-1 on their way to Nellis Air Force Base, Nev., Jauary 23, 2015. The F-15s are assigned to the 4th Fighter Wing. U.S. (Photo by Airman 1st Class Aaron J. Jenne/Reuters)

A moon appears behind a windmill a day before the supermoon is full on September 8, 2014 in Consuegra, in Toledo province, Spain. Consuegra belongs to a region made famous by the novel “Don Quijote de la Mancha” (Don Quixote) writed by Miguel De Cervantes. Some of the windmills belong to the 16th century. (Photo by Pablo Blazquez Dominguez/Getty Images)

A man dressed as a devil performs during a Krampus show, the traditional parade where people in costumes and masks perform an old ritual to disperse the ghosts of winter, in the southern Bohemian town of Kaplice, December 10, 2016. (Photo by David W. Cerny/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)

In this March 15, 2012 file photo, a Chinese woman poses for photos near a sculpture depicting a Chinese yuan note at an art district in Beijing, China. China devalued its tightly controlled currency on Tuesday, August 11,2015, following a slump in trade, triggering the yuan's biggest one-day decline in a decade. The central bank said the yuan's 1.3 percent fall was due to a change aimed at making its exchange rate controls more market-oriented. But any change raises the risk of tensions with China's trading partners. (Photo by Ng Han Guan/AP Photo)

Mrs. Marie Graskamp of Milwaukee shows the different positions one might assume when entering the bomb shelter in Milwaukee September 3, 1958. This circular entrance is about three feet in diameter. This is the entrance (according to the builders) that would connect to the cellar of a home assuming the shelter was in the ground for added protection. If a bombing should occur, all members of family would proceed to the cellar and then through the circular port into the shelter. (Photo by AP Photo)

A hogweed bonking beetle and yellow dung fly in a stalk standoff (the fly gave in), in Burley-in-Wharfedale, Yorkshire, England. (Photo by Rebecca Cole/Alamy Stock Photo)

Rockhopper penguins live up to their name as they navigate the rugged coastline of Marion Island in the southern Indian Ocean. (Photo by Thomas P. Peschak)