Troops of the Interior Ministry take part in a parade during a ceremony marking the Iraqi Police Day at a police academy in Baghdad January 9, 2016. (Photo by Khalid al Mousily/Reuters)

A figure of a skeleton is seen painted in a hallway of the house built underground by Manuel Barrantes in San Isidro de Perez Zeledon, Costa Rica, March 14, 2016. Barrantes started digging through red soil and volcanic rock on his farm 12 years ago to build his subterranean house, between 15 and 63 feet (4.57 and 19.2m) underground. The dwelling, which Barrantes says provides a peaceful and comfortable home for him and his family away from noise pollution and the effects of climate change, now covers about 2,000 square feet (185.8 square metres). (Photo by Juan Carlos Ulate/Reuters)

India's Central Reserve Police Force personnel take part in a rehearsal for the Republic Day parade on a cold winter morning in New Delhi January 8, 2014. (Photo by Ahmad Masood/Reuters)

North Koreans wave as Hughes MD-500 helicopters fly past during an aerial display on Saturday, September 24, 2016, in Wonsan, North Korea. North Korea on Saturday opened an air festival featuring sky diving, demonstrations by its air force and lots of beer to promote a newly renovated and upgraded commercial airport in the coastal city of Wonsan that it hopes will draw for foreign tourists. (Photo by Wong Maye-E/AP Photo)

Young couples compete in Rock' n'Roll & Co, an all- Russian acrobatic rock' n'roll competition in Kazan, Russia on November 4, 2017. Acrobatic rock’n’roll is a discipline for couples combining energetic dancing with acrobatic moves. (Photo by Yegor Aleyev/TASS via Getty Images)

A woman watches the rain from inside a stranded vehicle on a flooded street in Mianyang, Sichuan, China on July 11, 2018. (Photo by China News Service via Reuters)

Flames rage through a pile of tires at the tire dump of Sesena in Toledo, Spain, 13 May 2016. The tire dump reportedly contains over 100,000 tons of tires and reaches to the neighbouring town of Valdemoro in Madrid. According to local authorities, the fire was apparently deliberately started as it had been raining till midnight and the fire started early 13 May 2016 at a small spot in Valdemoro. (Photo by Ismael Herrero/EPA)

Tourists from the Middle East take pictures at Vrelo Bosne nature park in Ilidza near Sarajevo, Bosnia and Herzegovina, August 19, 2016. They discovered mountainous Bosnia, where half the population is Muslim, after the Arab Spring which destabilized many traditional holiday destinations such as Libya, Tunisia and Egypt. (Photo by Dado Ruvic/Reuters)