North Korean commuters are seen through a door window waiting to board a train in a subway train station in Pyongyang, North Korea, 14 April 2017. North Koreans are preparing to celebrate the “Day of the Sun” festival, commemorating the 105th birthday anniversary of former supreme leader Kim Il-sung on 15 April, as tension over nuclear issues rise in the region. (Photo by How Hwee Young/EPA)

“I was on Durga Puja Festival vacation, travelling on a local train. A boy was singing devotional song and begging for alms. He was guised as a Hindu god, Lord Shiva. This is a common view in Indian trains but this boy was charming, bright and did have a melodious voice. My camera was ready hanging on my neck so I took a picture”. (Photo and caption by Arup Ghosh/2014 Sony World Photography Awards)

Japanese Ground Self-Defense Force's 1st Airborne Brigade soldiers board a CH-47 helicopter for parachute drop training during their military drill at Higashifuji training field in Susono, west of Tokyo, July 8, 2013. Japan faces increasingly serious threats to its security from an assertive China and an unpredictable North Korea, a defence ministry report said on Tuesday, as ruling politicians call for the military to beef up its ability to respond to such threats. (Photo by Issei Kato/Reuters)

A woman sits next to a Gollum figure on the “Middle-earth Shuttle” subway train November 18, 2003 in New York City. The train's cars were decorated with Middle-earth creatures, vines, moss and stones to celebrate the November 18 DVD and VHS release of the Special Extended Edition of The Lord of the Rings: The Two Towers. (Photo by Mario Tama/Getty Images)

Men look out from a carriage train as it leaves from the Nizamuddin Railway Station on February 06, 2012 in New Delhi, India. The Nizamuddin Railway Station serves as the main station connecting all major cities, and is served by Northern Railways. (Photo by Daniel Berehulak/Getty Images)

Ford displays the drive train of the F150 Raptor SVT truck during the media preview of the Chicago Auto Show at McCormick Place on February 8, 2012 in Chicago, Illinois. The show, which is the largest and oldest auto show in the country, opens to the public on February 10. (Photo by Scott Olson/Getty Images)

An instructor (C) adjusts the posture of students of flight attendant major during a training session at Anhui Foreign Languages University, in Hefei, Anhui province, China, May 25, 2015. (Photo by Reuters/China Daily)

A Polish Army tank takes part in the NATO Noble Jump exercise on a training range near Swietoszow Zagan, Poland, Thursday, June 18, 2015. (AP Photo/Alik Keplicz)