A US Air Force (USAF) F-117A Nighthawk Stealth Fighter aircraft flies over Nellis Air Force Base (AFB), Nevada (NV), during the joint service experimentation process dubbed Millennium Challenge 2002 (MC02). (Staff Sgt. Aaron Allmon II via Wikimedia Commons).
German Chancellor Angela Merkel speaks during a press conference following a so-called "Diesel Summit" with mayors of large German cities in the chancellery in Berlin on Nov. 28, in order to look at ways of improving air quality. (John MacDougall/AFP/Getty Images)
U.S. Army Staff Sgt. Christopher Pearce sits next to a young boy during a visit to Shiek Burhan Al Asee's house during a patrol of the Riyahd village in Iraq on March 8, 2007. (U.S. Air Force photo by Master Sgt. Andy Dunaway)
Aaron Burr, the third vice president of the United States; U.S. President Donald Trump on the South Lawn of the White House Dec. 4, in Washington, D.C. (The New York Historical Society via Wikimedia Commons; Alex Wong/Getty Images)