Members of the Indonesian Presidential Security Forces (Paspampres) show their skills during the simulation of a terrorist attack in Jakarta, Indonesia, 29 December 2016. According to reports in local media the Indonesian security forces have already arrested 21 terrorists suspects and fatally shot five of them, who were allegedly planning attacks in the Indonesian capital during the Christmas and New Year's Eve celebrations this year. The presentation was shown on the occasion of a visit by Indonesian President Joko Widodo and a delegation to the Paspampres headquarters in Jakarta. (Photo by Bagus Indahono/EPA)

Israeli soldiers cry during a state memorial ceremony marking two years since the 2014 Gaza war “Operation Protective Edge” at Mount Herzl military cemetery in in Jerusalem, Israel, 26 July 2016. More than 2.000 people were killed in the conflicts between Israel and Palestine. (Photo by Abir Sultan/EPA)

A Ka'apor Indian warrior (L) chases a logger who tried to escape after they captured him during a jungle expedition to search for and expel loggers from the Alto Turiacu Indian territory, near the Centro do Guilherme municipality in the northeast of Maranhao state in the Amazon basin, August 7, 2014. Tired of what they say is a lack of sufficient government assistance in keeping loggers off their land, the Ka'apor Indians, who along with four other tribes are the legal inhabitants and caretakers of the territory, have sent their warriors out to expel all loggers they find and set up monitoring camps in the areas that are being illegally exploited. (Photo by Lunae Parracho/Reuters)

Engine driver Josef Kowatsch (top L) steers a train through the NEAT Gotthard Base Tunnel during a media visit near the town of Erstfeld August 24, 2015. Crossing the Alps, the world's longest train tunnel should become operational at the end of 2016, consisting of two parallel single track tunnels, each of a length of 57 km (35 miles). (Photo by Arnd Wiegmann/Reuters)

Athlets run during the women's 3000 meter steeplechase at the International Athletics Meeting in Lucerne, Switzerland, 14 June 2016. (Photo by Alexandra Wey/EPA)

World Champion Matthias Dolderer of Germany flies over the Horseshoe Bend near Lake Powell in Page, United States during the transfer flight from Indianapolis to Las Vegas to prior the final stage of the Red Bull Air Race World Championship on October 12, 2016. (Photo by Predrag Vuckovic/AFP Photo)

Street musicians with their faces covered with animal masks play to earn some money in central Vienna, Austria, November 8, 2015. (Photo by Vasily Fedosenko/Reuters)

Two 70 thousand RMB (about 11,310 USD) robots carry dishes and offer service for customers at a robot themed restaurant at Chunxi Road in Chengdu, China, December 11, 2014. The restaurant has 10 robots to serve as waiters. Each robot can carry simple dishes and offer simple greetings. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)