Iggy Azalea (L) and Ariana Grande perform onstage during the 2014 Billboard Music Awards held at MGM Grand Garden Arena on May 18, 2014 in Las Vegas, Nevada. (Photo by Michael Tran/FilmMagic)

Collided passenger train cars are seen in Taebaek, South Korea, Tuesday, July 22, 2014. Two passenger trains collided head-on in eastern South Korea on Tuesday afternoon, killing one passenger and injuring dozens, fire officials said. (Photo by AFP Photo/Yonhap)

«Mignon 2». A.E.G., Berlin, Germany, 1905. Despite its unusual appearance, the Mignon typewriter is of a very clever design, giving a smooth and fast operation for typing. (Photo and caption by Martin Howard/Martin Howard Collection)

Breitling Wingwalker Freya Paterson, from Liverpool, UK, flies above Kuwait City's iconic Water Towers with pilots David Barrell and Martyn Carrington, on March 6, 2014. The team loop and roll up to 160 mph enduring G-forces of 4-5g. Crowds are expected to line the Kuwaiti coastline to catch a glimpse of the Wingwalking team on Saturday, March 8, 2014, to mark the opening of the first dedicated boutique in the city for the prestigious watch brand. (Photo by Katsuhiko Tokunaga/Breitling)

Shepherds from the north wear their traditional heavy woollen mantles as they stand ready to shear sheep with sycthe-like shears. (Photo by Three Lions/Getty Images). Circa 1952

Cheerleaders wait to perform before the New Year's Day parade in London, Britain January 1, 2017. (Photo by Neil Hall/Reuters)

A devotee smiles as she offers prayers during the Swasthani Brata Katha festival in Kathmandu, Nepal January 12, 2017. (Photo by Navesh Chitrakar/Reuters)

People dressed as zombies take part in a “Zombie Walk” parade in Athens, Greece, February 25, 2017. (Photo by Michalis Karagiannis/Reuters)