Photos of Edward Snowden, a contractor at the National Security Agency (NSA), and U.S. President Barack Obama are printed on the front pages of local English and Chinese newspapers in Hong Kong in this illustration photo June 11, 2013. Snowden, who leaked details of top-secret U.S. surveillance programs, dropped out of sight in Hong Kong on Monday ahead of a likely push by the U.S. government to have him sent back to the United States to face charges. (Photo by Bobby Yip/Reuters)

This August 28, 2017 photo shows eight-year-old Indian girl Bharti performing a balancing act on a rope during a street show in Batala, India. Travelling Indian performers, who earn a meagre income from putting on shows on the streets, often scout areas to gather a large street audience who then give money on a collection plate at the end of the show. (Photo by Narinder Nanu/AFP Photo)

An applicant try-out during a stewardess recruiting interview for China Southern Airlines on October 12, 2006 in Beijing, China. Over 160 candidates have competed at the Beijing Region selection for a total of 15 berths in the next stage of recruitment. The China Southern Airlines launched a nationwide campaign to single out qualified stewardesses, the first of its kind to recruit stewardesses through TV shows. (Photo by China Photos/Getty Images)

A young girl navigates her way around Hampton Court maze in the spring sunshine on May 2, 2009 in London, England. The Hampton Court maze is one of the most famous hedge mazes in the world and was planted between 1689 and 1695 by George London and Henry Wise. (Photo by Dan Kitwood/Getty Images)

Myanmar revellers take part in celebrations on the fifth and last day marking Thingyan, a water festival which brings in the country's new year, in Yangon on April 16, 2016. The Buddhist festival of water pouring symbolizes spiritual cleansing and begin the new year free from worldly impurities with celebrants devoting the four days of Thingyan in merry making of water dousing until the eve of new year. (Photo by Romeo Gacad/AFP Photo)

A young man, who says he is part of a local criminal gang, poses for a picture holding a gun in the neighbourhood of Korogcho in Nairobi, Kenya, March 19, 2015. Around 2 million people live in the shantytowns packed in around Kenya's capital. Crime is high amid chronic unemployment levels, while basic services and sanitation are scarce. Residents try to make the best of things, eking out a living and picking up work where they can. (Photo by Siegfried Modola/Reuters)

In this photo provided by Jean Revillard, Solar Impulse 2, a plane powered by the sun's rays and piloted by Andre Borschberg, approaches Kalaeloa Airport near Honolulu, Friday, July 3, 2015. His 120-hour voyage from Nagoya, Japan broke the record for the world's longest nonstop solo flight, his team said. (Photo by Jean Revillard/Global Newsroom via AP Photo)

A Santa Claus puppet holding a Christmas tree is pictured against the sun in Berlin November 23, 2014. (Photo by Hannibal Hanschke/Reuters)