Private Harold L. Langhofer edges into the ball-turret, March 9, 1943. Curled in this position, he can turn the turret so that it fires in any direction. The turret can also be swung around so that the hatch opens into the plane, and the gunner can crawl into it while the Flying Fortress is in motion. (Photo by AP Photo)

A pilot inflates a hot air balloon while taking part in the 38th International Balloon Festival of Chateau-d'oex, Switzerland, 23 January 2016. The festival takes place from 23 to 31 January. (Photo by Vincent Vannay/EPA)

This plane looks like it's bound for the moon as it shoots across the sky. Photographer Sebastien Lebrigand was impressed he could even see the lights on the jet's wings in this stunning silhouette. (Photo by Sebastien Lebrigand/Solent News)

The sun rises beside St Mary's Lighthouse in Whitley Bay, Tyne and Wear, as the unseasonably cool weather continues on Thursday, April 28, 2016. (Photo by Owen Humphreys/PA Wire)

Waves hit the seawall during heavy seas and high winds in Dawlish in south west Britain, February 2, 2017. (Photo by Toby Melville/Reuters)

Masked Guggen music bands parade through the streets on the occasion of the beginning of the Fasnacht Carnival of Lucerne, Switzerland, early 23 February 2017. (Photo by Urs Flueeler/EPA)

In this November 12, 2015, file photo, Mt. Everest is seen from the way to Kalapatthar in Nepal. An American climber has died near the summit of Mount Everest and an Indian climber is missing after heading down from the mountain following a successful ascent, expedition organizers said Sunday. (Photo by Tashi Sherpa/AP Photo)