An actor plays an injured passer-by during Exercise Strong Tower, the scene of a mock terror attack at a disused underground station in central London, Britain June 30, 2015. London police held their biggest-ever terrorism drill on Tuesday, pitting the emergency services against a group of marauding attackers, nearly 10 years since four young British Islamists killed 52 people in suicide bombings on London's transport network in July 2005. (Photo by Peter Nicholls/Reuters)

A man performs ablution using water at an old fountain before performing prayers in the old city of Algiers Al Casbah, Algeria December 3, 2015. The Algiers Casbah is a UNESCO World heritage site that includes the Sidi Ramdane mosque and former fortress, 10 centuries old. Decay from the passing years, as well as earthquake damage in 2003, leads some to consider a move to modern apartments with financial backing from the government. Others refuse to leave a neighbourhood they have called home for decades. (Photo by Zohra Bensemra/Reuters)

Afghan children wait as their mothers receive treatment at a USAID-funded health center on September 7, 2011 in Farza, Afghanistan. Almost 10 years after the 9/11 attacks and the U.S. invasion of Afghanistan, the U.S. government funds some of 500 Afghan health facilities nationwide, most run by non-governmental organizations contracted by the Afghan Ministry of Public Health. (Photo by John Moore/Getty Images)

An Afghan child practices walking with his new prosthesis at the International Committee of the Red Cross (ICRC), orthopedic center on September 10, 2011 in Kabul, Afghanistan. After more than 30 years of war and a decade since the 9/11 attacks in the United States, thousands of Afghans, both military and civilian, continue to pay a heavy price from the conflict. The ICRC center makes prosthetics for amputees and helps them, as well as Afghans with spinal injuries and children with congenital birth defects, to learn to walk. (Photo by John Moore/Getty Images)

A Thai man smokes a cigarette as he sits in the flooded streets October 10, 2011 in Ayutthaya, Thailand. Around 200 factories closed in the central Thai province of Ayutthaya because of flooding, which is posing a threat to Bangkok as well. Over 260 people have died in flood-related incidents since late July according to the Department of Disaster Prevention and Mitigation. Some areas of the country are experiencing the worst flooding in 50 years, mainly in the centre, north and northeast. (Photo by Paula Bronstein /Getty Images)

Mikhail Baburin, 66, talks to his cat Marquis at his house in the remote Siberian village of Mikhailovka, Krasnoyarsk region, Russia, December 5, 2016. Baburin, a former Navy man, barge worker and employee of a military plant in Krasnoyarsk, is the last inhabitant of Mikhailovka, which was founded in the 19th century by migrants from Russia's Mordovia region. He moved in 2000 to Mikhailovka where he was born and has lived there all alone for the last 10 years with only domestic animals. (Photo by Ilya Naymushin/Reuters)

A man sleeps between tombstones in front of his single-room home on a hot night in the Cairo Necropolis, Egypt, October 13, 2015. In the sprawling Cairo Necropolis, known as the City of the Dead, life and death are side by side. Amid a housing crisis in Egypt, and with the population of greater Cairo estimated at about 20 million, people count themselves lucky to have a place to call home in the graveyards that date back hundreds of years. (Photo by Asmaa Waguih/Reuters)