An F-18 Hornet of the Finnish Air Force refuels from a U.S. Air Force KC-135 Stratotanker from RAF Mildenhall, England, following aerial refueling over Finland, May 25, 2017. Both aircraft are participating in Arctic Challenge 2017, a multinational exercise encompassing 11 nations and more than 100 aircraft. (U.S. Air Force photo by Tech. Sgt. David Dobrydney)