Firefighters attempt to put out a fire at an abandoned building with the protection of St. Louis City Police in St. Louis, Missouri August 19, 2015. Police fatally shot a black man they say pointed a gun at them, drawing angry crowds and recalling the racial tensions sparked by the killing of an unarmed African-American teen in nearby Ferguson, Missouri, just over a year ago. (Photo by Lawrence Bryant/Reuters)

A 10 week old stuffed Tiger cub and a Tortoise are displayed in a cabinet at an “Endangered Species” exhibition at London Zoo on September 12, 2011 in London, England. The exhibition is organised by “Operation Charm”, a Metropolitan Police partnership aimed at tackling the illegal trade in endangered wildlife and runs for one month at London Zoo. Items include the tooth of a sperm whale, Ivory carvings, and a stuffed Tiger. (Photo by Dan Kitwood/Getty Images)

Newly commissioned 2nd lieutenants throw their caps in the air as a team of F-16 Air Force Thunderbirds fly over the 2011 graduating class of the U.S. Air Force Academy on May 25, 2011 in Colorado Springs, Colorado. A total of 1,021 graduates received their diplomas in front of their families and dignitaries at the Academy's Falcon Stadium. (Photo by John Moore/Getty Images)

Hot air balloons are prepared for a flight as others take off during an international hot air balloon festival at Maayan Harod National park in northern Israel September 30, 2015. (Photo by Baz Ratner/Reuters)

A C-17 Globemaster III crew prepares an air refueling mission September 27, 2012, at Joint Base Charleston, S.C. (Photo by Airman 1st Class Matthew J. Bruch/U.S. Air Force photo)

A view of a Van Gogh-inspired hot air balloon being inflated during the Philippine International Hot Air Balloon Fiesta at Clark Freeport Zone in Pampanga province, north of Manila February 12, 2015. According to the organizer, a total of 32 hot air balloons are part of the four-day event. (Photo by Erik De Castro/Reuters)

In this photo provided by Andreas Langreiter via Global-Newsroom, Hannes Arch of Austria performs during the finals of the first stage of the Red Bull Air Race World Championship in Abu Dhabi, United Arab Emirates, Saturday, February 14, 2015. (Photo by Andreas Langreiter/AP Photo/Global-Newsroom)