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)

Iranian women perform as they train Far East Fighting Arts to be able to defend themselves, at the Jughin castle which is located 40 km's far from Tehran, Iran on June 5, 2017. (Photo by Fatemeh Bahrami/Anadolu Agency/Getty Images)

A marine aims an RPG-7, a portable rocket- propelled grenade launcher, during military exercises conducted by the Russian Pacific Fleet' s naval infantry unit at the Bamburovo firing range on February 2, 2017. The drills are a part of preparations for the Suvorov Attack and Sniper Line army competitions. (Photo by Yuri Smityuk/TASS)

Colombia midfielder Natalia Gaitan (3) goes up for a header against Mexico midfielder Nayeli Rangel (7) in Moncton, June 9, 2015. (Photo by Matt Kryger/USA TODAY Sports)

Pedestrians and vehicles make their way past the Potala Palace early on a rainy morning in Lhasa, capital of the Tibet Autonomous Region in China, Saturday, September 19, 2015. Chinese officials have taken foreign journalists on a visit to the region, normally off-limits to them, weeks after Communist Party officials commemorated the 50th anniversary of the establishment of the Tibet Autonomous Region. (Photo by Aritz Parra/AP Photo)

Typhoon Bopha moves toward the Philippines, observed from the ISS, on December 2, 2012. (Photo by AP Photo/NASA via The Atlantic)