Seljalandsfoss waterfall, located in Iceland. Seljalandsfoss is one of the most famous waterfalls of Iceland. This waterfall of the river Seljalandsá drops 60 metres (200 ft) over the cliffs of the former coastline. It's possible to go behind the waterfall. (Photo by HotSpot Media)

Paramedics carry an injured woman out from a subway station after a rush-hour subway train derailment, to be transported by a medical helicopter in Moscow, Russia, on Tuesday, July 15, 2014. A rush-hour subway train derailed in Moscow Tuesday, killing 20 people and injuring at least 150, emergency officials said. Several cars left the track in the tunnel after a power surge triggered an alarm, which caused the train to stop abruptly. (Photo by Ivan Sekretarev/AP Photo)

An internally displaced Afghan girl holds a child at a refugee camp in Kabul, Afghanistan May 31, 2016. (Photo by Mohammad Ismail/Reuters)

People march past the Colosseum during the Gay Pride parade in Rome, Saturday, June 11, 2016. Italy joined the rest of Europe last month in giving some legal rights to gay couples after a years-long battle and opposition from the Catholic Church to anything that smacked of authorizing gay marriage. (Photo by Fabio Frustaci/AP Photo)

A coach watches as one of her squad members practices during the Legacy Super Regional Cheer and Dance Championships at Copperbox Arena, Queen Elizabeth Olympic Park in London, Britain, February 19, 2017. (Photo by Toby Melville/Reuters)

A traditional Russian nesting doll painted with the likeness of President of Donald Trump and his family is displayed for sale at a Moscow store on March 5, 2017 in Moscow, Russia. Relations between the United States and Russia are at their lowest point in years as evidence mounts about the complex relationship between President Donald Trump's administration and the Russian government. (Photo by Spencer Platt/Getty Images)

A girl takes a nap during a Christmas eve mass at a Catholic church on the outskirts of Taiyuan, North China's Shanxi province, December 24, 2016. (Photo by Jason Lee/Reuters)

Boats moored in the middle of Dal lake are silhouetted against the setting sun on January 15, 2018 in Srinagar, the summer capital of Indian administered Kashmir, India. Kashmir, the Muslim majority state, known as the “Paradise on Earth” has for centuries captured the imagination of many writers, poets and film makers and is integral to the tourist trade. Kashmir has been a contested land between nuclear neighbors India and Pakistan since 1947, the year both the countries attained freedom from the British rule. (Photo by Yawar Nazir/Getty Images)