Children wave Vietnamese and American flags while waiting for arrival of U.S. President Barack Obama (not pictured) before a welcoming ceremony at the Presidential Palace in Hanoi, Vietnam May 23, 2016. (Photo by Reuters/Kham)

A view of the scene of a train accident after two commuter trains collided head-on near the town of Andria, in the southern region of Puglia, killing several people, Tuesday, July 12, 2016. (Photo by Luca Turi/ANSA via AP Photo)

A woman is having a massage at the Lukacs Bath in Budapest, Hungary June 28, 2016. Hungary's capital owes its popularity as a tourist destination partly to its numerous hot springs and bathing culture which have drawn visitors to the area since Roman times. Bath houses range from large, ornate 19th-century buildings like the Gellert and the Szechenyi to tiny Ottoman Turkish-era hamams, some of them more than 500 years old. (Photo by Bernadett Szabo/Reuters)

In this photograph taken on August 25, 2016, an Afghan shepherd watches over his sheep as they graze on the outskirts of Herat. (Photo by Aref Karimi/AFP Photo)

People sit on a cart with a camel tied to it during “Temeenii bayar”, the Camel Festival, in Dalanzadgad, Umnugobi aimag, Mongolia, March 6, 2016. On the steppes of the Gobi Desert, the crowd urges on Bactrian camels laden down with all that's needed to build and live in a traditional Mongolian tent. Guinness World Records classes the 15 km race thatÕs part of the two-day festival as the largest camel race in the world, drawing 1,108 participants. The winning camel romped home in 35 minutes and 12 seconds, according to the records website. (Photo by B. Rentsendorj/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)

Demonstrators take part in a mass “face-sitting protest” outside the Houses of Parliament in central London on December 12, 2014, as they protest against changes to p*rnography regulations. An amendment to the 2003 Communities Act applies the same strict rules to p*rn bought online as those included in the guidelines set out by the British Board of Film Censors for DVDs. The new laws ban films that feature s*x acts, such as spanking, caning, strangulation, aggressive whipping, humiliation, and face-sitting. Ministers say the rules have been brought in to protect s*x workers. But campaigners say it is an attempt to censor and control the internet. Paid-for videos shot overseas and viewed online in the UK are not affected by the new rules, which were introduced on December 2, 2014. (Photo by Leon Neal/AFP Photo)

An internally displaced Afghan girl plays near their shelter at a refugee camp in Kabul January 13, 2015. (Photo by Omar Sobhani/Reuters)