Singer Ariana Grande (C) performs “Side by Side” during the 2016 American Music Awards in Los Angeles, California, U.S., November 20, 2016. (Photo by Mario Anzuoni/Reuters)

Robot pianist Teo Tronico performs at the World Robot Conference (WRC) 2017 at Etrong International Exhibition & Convention Center on August 22, 2017 in Beijing, China. The World Robot Conference 2017 is held from August 23 to 27 in Beijing. (Photo by Liu Guanguan/China News Service/VCG via Getty Images)

Ethnic Miao women wearing traditional costumes take part in a parade during the traditional Lusheng (reed-pipe wind instrument) festival in Gulong, Guizhou province, China November 15, 2017. (Photo by Reuters/China Stringer Network)

Blankets cover the bodies of a woman (right) and a man (left background) hit by a northbound Penn Central train (background) as they waited with a crowd at Pennsylvania Railroad station in Elizabeth, N.J. on June 8, 1968 to view the southbound train carrying the body of Sen. Robert F. Kennedy to Washington. The woman was identified as Mrs. Antoinette Severini, 54, and the man, John Curia (age unavailable), both of Elizabeth. (Photo by AP Photo)

A dancer warms up backstage before the final of the 46th Prix de Lausanne, in Lausanne, Switzerland, 03 February 2018. Launched in 1973, the Prix de Lausanne is an international dance competition for young dancers aged 15 to 18. Closing the six-day event, prizes are awarded to the best of 21 finalists consisting of scholarships granting free tuition in a world-renowned dance school or dance company. (Photo by Valentin Flauraud/EPA/EFE)

A string is used to ensure that the skirts of female members of the honour guard are in the same height from the ground as they prepare for a welcoming ceremony for Congo Republic President Denis Sassou Nguesso outside the Great Hall of the People in Beijing, China, July 5, 2016. (Photo by Jason Lee/Reuters)

In this Friday, February 6, 2015 photo, sandhill cranes begin to stir after resting for the night at a roosting location along their winter migration route in Cecilia, Ky. According to counts made by biologists with the Kentucky Fish and Wildlife Resources, about 12,000 of the birds have stopped in Cecilia this week during their winter northward migration on their way to their nesting grounds in the Great Lakes region. (Photo by David Stephenson/AP Photo)

This photo provided by Steamboat Ski Resort shows hot air balloons that visitors can tour in above the town and mountains in Steamboat Springs, Colo. Wild West Adventures offer continental breakfast, champagne ceremony with flight certificates and courtesy pick-up are included. (Photo by Larry Pierce/AP Photo/Steamboat Ski Resort)