Londoners sleep on the platform and on the train tracks at Aldwych Underground station,London, during heavy all night Nazi bombing raids, October 8, 1940. (Photo by AP Photo)

DJ Evans Mireku Kissi (R) and fashion stylist Daniel Quist ride a motorcycle in front of a street side bar in Accra, Ghana. June 10, 2015. Young artists in Ghana's capital have evolved a new style that is turning heads and challenging accepted notions of African fashion. (Photo by Francis Kokoroko/Reuters)

Visitors wear shirts with an image of former Chinese leader Mao Zedong at the Shanghai World Expo site in Shanghai, May 2, 2010. (Photo by Aly Song/Reuters)

A students with her face smeared in coloured powder, celebrates Holi at a university campus in Chandigarh, India March 23, 2016. (Photo by Ajay Verma/Reuters)

Indonesian mahouts (elephant masters) bathe elephants prior to a daily patrol at a Conservation Respons Unite (CRU) to control elephant-human conflicts in Serbajadi, East Aceh on April 7, 2016. Elephants have joined the front line in the fight against poaching and illegal logging in the dense jungles of Sumatra. Guided by their Indonesian mahouts, they trek alongside rivers, over rough terrain and deep into the rainforest in an area that is home to numerous endangered species, from orangutans to tigers, but which has suffered devastating deforestation in recent years. (Photo by AFP Photo/Januar)

Laborers work on scaffolding near a full-scale replica of the Sphinx at an unfinished movie and animation tourism theme park, in Chuzhou, Anhui province, March 27, 2015. (Photo by Reuters/China Daily)

Ayesha Farooq, 26, Pakistan's only female war-ready fighter pilot watches an airforce jet about to take off at Mushaf base in Sargodha, north Pakistan June 7, 2013. Farooq, from Punjab province's historic city of Bahawalpur, is one of 19 women who have become pilots in the Pakistan Air Force over the last decade – there are five other female fighter pilots, but they have yet to take the final tests to qualify for combat. A growing number of women have joined Pakistan's defence forces in recent years as attitudes towards women change. (Photo by Zohra Bensemra/Reuters)

A boy looks back while he and another boy play on a Syrian military tank, destroyed during fighting with the Rebels, in the Syrian town of Azaz, on the outskirts of Aleppo, Sunday, September 2, 2012. (Photo by Muhammed Muheisen/AP Photo)