People smear black ash with hands onto each other to wish for good luck and fortune during a traditional festival of the Yi ethnic minority in Qiubei County, Yunnan province, China July 18, 2017. (Photo by Ren Dong/Reuters/CNS)

A performer dances at a housing exhibition in Wuhan, Hubei province, China, September 27, 2015. (Photo by Reuters/Stringer)

Palestinian schoolboys sit in the trunk of a car as they go to school on a rainy day in Khan Younis, in the southern Gaza Strip, October 7, 2015. (Photo by Ibraheem Abu Mustafa/Reuters)

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 girl carries a picture of Sheikh Nimr al-Nimr, who was executed along with others in Saudi Arabia, during a protest against the execution in front of the United Nation's building in Beirut, Lebanon January 3, 2016. Sign reads, “The martyr scholar Nimr al-Nimr”. (Photo by Hasan Shaaban/Reuters)

Palestinian children warm themselves by a fire on a stormy day at Shati (beach) refugee camp in Gaza City January 18, 2016. (Photo by Mohammed Salem/Reuters)

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 Hindu sadhu (holy man) smears coloured paste onto his face ahead of the forthcoming Hindu festival of “Maha Shivaratri” at the Pashupatinath temple in Kathmandu on February 11, 2018. Hindus mark the “Maha Shivratri” festival by offering special prayers and fasting, with sadhus arriving at Pashupatinath to take part in the event, which takes place on February 13. (Photo by Prakash Mathema/AFP Photo)