A Palestinian youth jumps with a sword as he demonstrates his ninja-style skills for the photographer in front of the ruins of buildings, that were destroyed in 2014 war, in the northern Gaza Strip January 29, 2016. The youths, who have been receiving martial arts training at local clubs in Gaza for the past two years, decided to form a team to hold regular shows in the hope that the publicity generated will eventually lead to them being invited to participate in international contests. (Photo by Mohammed Salem/Reuters)

A man yells for help minutes after a Serb shell hit a crowded pedestrian walkway in Sarajevo, May 1993. Radovan Karadzic, a 70-year-old former psychiatrist, still in robust health, is the most senior political figure to be convicted by the International Criminal Tribunal for the Former Yugoslavia. He was found guilty of 10 out of 11 charges. He was acquitted of a second count of genocide in Bosnian towns. (Photo by Reuters)

Tourist take pictures at Mai Khao Beach, as a plane approaches the Phuket International Airport in Phuket, Thailand March 17, 2016. With its palm-fringed beaches, Buddhist culture and racy nightlife, Thailand has been the poster child for Asian tourism for decades, attracting a range of visitors from backpackers and adventure-seekers, to families and culture vultures. But dark clouds could be forming even as a record of 32 million tourists are expected this year. (Photo by Athit Perawongmetha/Reuters)

Participants dressed in historical clothing ride high-wheel bicycles during a bicycle ballet event at Schloss Karlsruhe palace during the 2017 International Veteran Cycle Association (IVCA) rally to celebrate the 200th anniversary of the bicycle on May 27, 2017 in Karlsruhe, Germany. Karl Drais, a German inventor, built and tested the first bicycle, called the Draisine, that ran without pedals in 1817. (Photo by Alexander Scheuber/Getty Images)

The Soyuz TMA-19M spacecraft is mounted on a launch pad at the Russian-leased Baikonur cosmodrome in Kazakhstan early on December 13, 2015. Russia's Soyuz TMA-19M spacecraft carrying the International Space Station (ISS) Expedition 46/47 crew of Britain's astronaut Tim Peake, Russian cosmonaut Yuri Malenchenko and US astronaut Tim Kopra is scheduled to blast off to the ISS on December 15, 2015. (Photo by Kirill Kudryavtsev/AFP Photo)

Hot air balloons fly over the sky in Chiang Mai province, northern Thailand, December 6, 2014. The two-day International Balloon festival 2014 featuring balloon pilots from Germany, Spain, Netherlands, Britain, and Czech Republic is held on December 06-07 2014 to celebrate Thai King Bhumibol Adulyadej's 87th birthday and also aimed to promote the tourism industry in Chiang Mai northern city. (Photo by Pongmanat Tasiri/EPA)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, run at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. Boko Haram says it is building an Islamic state that will revive the glory days of northern Nigeria's medieval Muslim empires, but for those in its territory life is a litany of killings, kidnappings, hunger and economic collapse. (Photo by Afolabi Sotunde/Reuters)

An Afghan woman fills containers with water near her temporary shelter at an internally displaced person's (IDP) camp on the outskirts of Herat, Afghanistan, January 21, 2015. Dozens of families are living in temporary shelters even in harsh winters and most depend on aid distributions by the United Nations High Commissioner for Refugees (UNHCR). (Photo by Jalil Rezayee/EPA)