Musicians of the alphorn band "Holdersberger Alp- Traum- Blaeser" perform their skills on a raft floating on the Elbsee lake near Aitrang, southern Germany, on June 11, 2017. (Photo by Karl-Josef Hildenbrand/AFP Photo/DPA)

Dinah Jane, from left, Normani Kordei, Lauren Jauregui, and Ally Brooke of Fifth Harmony perform a medley at the MTV Video Music Awards at The Forum on Sunday, August 27, 2017, in Inglewood, Calif. (Photo by Chris Pizzello/Invision/AP Photo)

In this picture taken Friday, September 8, 2017, Brazilan Samba dancers perform on stage during the Harare International Carnival in the capital. An international carnival aimed at boosting the local tourism industry has ended in economically troubled Zimbabwe. Some viewed the Harare festivities, which ended Sunday and featured artists and dancers from Brazil, Cuba, Egypt and elsewhere, as a relief from the struggle to get by in the southern African country. (Photo by Tsvangirayi Mukwazhi/AP Photo)

Heidi Klum, dressed as a werewolf, performs a dance from Michael Jackson's "Thriller" video her 18th Annual Halloween Party at Moxy Times Square on Tuesday, October 31, 2017, in New York. (Photo by Evan Agostini/Invision/AP Photo)

A performer poses during celebrations after Rahul Gandhi, newly elected president of India's main opposition Congress party, took charge as the president during a ceremony outside the party's headquarters in New Delhi, India, December 16, 2017. (Photo by Altaf Hussain/Reuters)

Dancers of the Czech National Ballet warm up backstage during a performance of “The Nutcracker – A Christmas Carol” at the National Theatre in Prague, Czech Republic, late 16 December 2017. Peter I. Tchaikovsky's “The Nutcracker”, one of his most famous compositions and seasonal ballets, premiered in St. Petersburg, Russia, on 18 December 1872, celebrates its 125th anniversary this year. (Photo by Martin Divisek/EPA/EFE)

Students of the Krasnoyarsk choreographic college Anastasia Shevtsova (R) and Yulia Lyakhovykh do leg-splits as they study for an exam and a performance by the graduates at the State Theatre of Opera and Ballet, at the college's campus in the Siberian city of Krasnoyarsk, Russia, May 4, 2017. (Photo by Ilya Naymushin/Reuters)

US President Donald Trump and First Lady Melania Trump watch the Florida Atlantic University Marching Band and cheerleaders perform prior to a Super Bowl party at Trump International Golf Club in West Palm Beach, Florida, February 4, 2018. (Photo by Saul Loeb/AFP Photo)