Željava Air Base, situated on the border between Croatia and Bosnia and Herzegovina under Plješevica Mountain, near the city of Bihać, Bosnia, was the largest underground airport and military air base in the former Yugoslavia, and one of the largest in Europe. (Photo by Thomas Windisch/Exclusivepix Media)

Afghan National Army (ANA) soldiers sit waiting to return their weapons after a day of traning at the Kabul Military Training Center (KMTC) October 3, 2010 in Kabul, Afghanistan. There are between 5,000 to 7,000 troops on the training facility in eight-week cycles trained by the coalition forces to ultimately take over the role of military operations in the country. (Photo by Paula Bronstein/Getty Images)

A participant tries to stay warm during the Macy's Thanksgiving Day Parade in Manhattan,New York, U.S., November 22, 2018. (Photo by Brendan McDermid/Reuters)

The Olaf balloon glides over Central Park West during the Macy's Thanksgiving Day Parade in New York, Thursday, November 23, 2017. The Macy's Thanksgiving Day parade is the largest parade in the world and has been held since 1924. (Photo by Craig Ruttle/AP Photo)

Girls suffering from dwarfism take part in the disability pride parade in New York, July 12, 2015. The parade grand marshal was former U.S. Sen. Tom Harkin, the Iowa Democrat who 25 years ago sponsored the Americans With Disabilities Act. (Photo by Eduardo Munoz/Reuters)

Participants wearing costumes take part in the West Indian Day Parade in the Brooklyn borough of New York September 1, 2014. The parade, which draws a crowd of a million plus, celebrates Caribbean culture. (Photo by Eric Thayer/Reuters)

A Felix the Cat balloon and other parade floats and balloons are led down Broadway during the annual Macy's Thanksgiving Day Parade; ca. 1900s, Broadway, Manhattan, New York City, New York State, USA. (Photo by Underwood & Underwood/Corbis)