Israeli soldiers play the parts of wounded civilians during a drill simulating a toxic spill from an attack on a train in Beersheba, southern Israel, 13 January 2016, as Home Front medical teams, fire fighters and police carry out rescue operations. The large scale drill is the concluding exercise of the Fourth International Conference on Healthcare System Preparedness and Response to Emergencies and Disasters and includes some 200 of the world's experts on health system readiness from around the world. The conference is dealing with all types of medical emergencies from terrorist attacks to natural disasters. (Photo by Jim Hollander/EPA)

Palestinian children warm themselves by a fire on a stormy day at Shati (beach) refugee camp in Gaza City January 18, 2016. (Photo by Mohammed Salem/Reuters)

Expedition 44 flight engineer and NASA astronaut Scott Kelly seen inside the Cupola, a special module which provides a 360-degree viewing of the Earth and the International Space Station. Kelly is one of two crew members spending an entire year in space. (Photo by Scott Kelly/NASA)

A Tibetan artists wearing a traditional costume waits before their performance during the 82nd pre-birthday celebration of Tibetan spiritual leader Dalai Lama at a Monastery in Kathmandu, Nepal, 05 July 2017. More than 1,000 monks and other Tibetans gathered at the Monastery compound to celebrate their spiritual leader's birthday. The Nepalese government has banned all kinds of Tibetan activities against the Chinese rule in Tibet so Tibetans have been changing the venue of the Dalai Lama's birthday celebration. The Dalai Lama will turn 82 on 06 July 2017. (Photo by Narendra Shrestha/EPA)

In this Wednesday, April 12, 2017, photo, waitresses wait outside a restaurant in Pyongyang, North Korea. A generational divide is quietly growing in North Korea, often hidden behind relentless propaganda. On the streets there are young women in not-quite mini-skirts and teenage boys with baseball hats cocked sideways, K-pop style. (Photo by Wong Maye-E/AP Photo)

Belarusian schoolchildren, who are members of a pro-government Young Pioneer movement, perform with drums as they take part in a meeting to mark the 95th anniversary of their organisation in Minsk, Belarus May 19, 2017. (Photo by Vasily Fedosenko/Reuters)

A Sphynx cat at the 2017 Grand Prix Royal Canin international cat show at the Crocus Expo Exhibition Centre in Moscow, Russia on December 2, 2017. (Photo by Sergei Savostyanov/TASS/Barcroft Images)

Two and a half year-old Jennifer Martin in tears during a visit to Santa at Harrods department store in London, 10th December 1949. (Photo by William Vanderson/Fox Photos/Hulton Archive/Getty Images)