Residents with faces covered in ash ride on a motorcycle as Mount Sinabung volcano erupts, in Sukandebi village in Karo Regency, Indonesia's North Sumatra province, Indonesia June 13, 2015, in this photo taken by Antara Foto. (Photo by Rony Muharrman/Reuters/Antara Foto)

A sculptural artwork depicting former Chilean dictator Augusto Pinochet and headless presidents shot by a hooded high school student (not pictured) is seen at the Contemporary Art Museum in Santiago, December 2, 2014. The artwork, part of the “El ladrillo angular” (The angular brick) exhibition, portrays a student fighting against the ongoing continuity of dictatorship because of a political and economic system which has been impossible to destroy, according to “Papas Fritas” the artwork's creator. (Photo by Ivan Alvarado/Reuters)

A bunker at aformer Swiss artillery fortress called Heldsberg stands near the town of St. Margareten, Switzerland March 22, 2015. Heldsberg fortress, located on the Swiss-Austrian border near the River Rhine and Lake Constance was built from 1938 to 1940 and remained in military use until 1992. Since 1993 it is open to the public as Fortress Museum Heldsberg. (Photo by Arnd Wiegmann/Reuters)

A woman takes part in the procession of the “Virgem da Atalaia” procession during Holy Week at Alcochete, near Lisbon, Portugal March 27, 2016. Women ride on donkeys during the “Virgem da Atalaia” procession, that has been held annually for about 400 years. In the past, only single women rode the donkeys to ask for help from the Virgin to find a husband. (Photo by Rafael Marchante/Reuters)

Subway passengers walk past bronze sculptures representing the Soviet people at the Ploshchad Revolyutsii metro station in Moscow, on November 14, 2012. The station was opened in 1938. (Photo by Kirill Kudryavtsev/AFP Photo)

An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)

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)

A woman wades through a flooded village in the eastern state of Bihar, India August 22, 2017. (Photo by Cathal McNaughton/Reuters)