A worker stands under the Airlander 10 hybrid airship during its unveiling in Cardington, Britain March 21, 2016. The world's largest aircraft has been unveiled for the first time since being fully assembled in the UK. The 302ft (92m) long Airlander 10 – part plane, part airship – was floated in a First World War hangar in Bedfordshire. (Photo by Darren Staples/Reuters)

Kurdish pesh merga troops fire at Islamic State positions as they move toward the Iraqi town of Badana Pichwk on Monday morning, October 17, 2016. Kurdish forces began Monday advancing on a string of villages east of Mosul, the start of a long-awaited campaign to reclaim Iraq's second-largest city from the Islamic State, which seized it more than two years ago, officials said. (Photo by Bryan Denton/The New York Times)

This image obtained January 31, 2017 from the US Geological Survey's Hawaiian Volcano Observatory showing a lava stream, pouring out of the lava tube on the sea cliff at the Kamokuna ocean entry from the Kilauea Volcano on January 29. (Photo by AFP Photo/USGS)

An Egyptian carries bread tray over his bicycle, in Cairo, Egypt, Saturday, November 19, 2016. Egypt is currently suffering an acute foreign currency shortage because of the decimation of its lucrative tourism industry, double digit rates of inflation and unemployment. (Photo by Amr Nabil/AP Photo)

A Rohingya refugee woman is helped from a boat as she arrives exhausted on the Bangladesh side of the Naf River at Shah Porir Dwip after fleeing her village in Myanmar, on October 1, 2017 in Cox's Bazar, Bangladesh. (Photo by Kevin Frayer/Getty Images)

Model Amanda Kaspor of Highland, Michigan poses with the CT&T e-Zone Plus electric car is displayed during the press preview for the world automotive media North American International Auto Show at the Cobo Center January 12, 2010 in Detroit, Michigan. (Photo by Bryan Mitchell/Getty Images)

Actors dressed up as zombies walk around while posing for photos with passers-by in New York's Times Square on Friday, October 10, 2014 as a promotion for the season premiere of AMC's “The Walking Dead” this Sunday, October 12, 2014. (Photo by Gordon Donovan)

German Oliver Struempfl competes to set a new world record in carrying one liter beer mugs over a distance of 40 m (131 ft 3 in) in Abensberg September 7, 2014. Struempfl carried 27 mugs over 40 meters to set a new record for the Guinness book of records. (Photo by Michael Dalder/Reuters)