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 works on “Long Ma”, a creation by La Machine production company, during a media visit to “A Journey to Nantes” (Le Voyage a Nantes) art festival in Nantes, France, June 30, 2015. The art festival will run from July 3 to August 30. (Photo by Stephane Mahe/Reuters)

SoftBank's human-like robot named “Pepper” poses for pictures in its role as a PR manager of Tottori prefecture at the prefecture speciality store in Tokyo, Japan, July 1, 2015. Pepper will work at the store until July 2, as the first workplace venue for its temporary staffing service. (Photo by Yuya Shino/Reuters)

Revellers try to hold on to a wild horse during the “Rapa das Bestas” traditional event in the village of Sabucedo, northwestern Spain, July 5, 2015. On the first weekend of the month of July, hundreds of wild horses are rounded up, trimmed and groomed in different villages in the Spanish northwestern region of Galicia. (Photo by Miguel Vidal/Reuters)

A Japan soccer fan reacts as she watches Japan's FIFA Women's World Cup final match against the U.S. in Vancouver, at a public viewing event in Tokyo, Japan, July 6, 2015. Japan lost the match 5-2 to the U.S. (Photo by Toru Hanai/Reuters)

These images of young children training were taken at a gymnastics summer camp in Bozhou, Anhui province, China on July 28, 2015. Children with promise are selected to attend, and their families hope training will not only benefit their children physically but also increase ‘willpower’, according to China News Service. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

Miniature books and furniture are displayed in the "library" of the Astolat Castle, a 3 metre (9 foot) tall dollhouse, currently on display in New York November 14, 2015. Appraised at $8.5 million, the Astolat Castle, weighs 363 kg (800 pounds) and has 29 rooms, according to local media. (Photo by Lucas Jackson/Reuters)

A woman carrying cabbage leaves on her head buys tomato at a market in Ahmedabad, India, November 9, 2015. India's villages face a sharp spike in food prices in 2016, as a second year of drought drives up the cost of ingredients such as sugar and milk, and poor transport infrastructure stops falling global prices from reaching rural areas. (Photo by Amit Dave/Reuters)