A dancer from the Trisha Brown Dance Company performs during “Roof Piece” above the High Line park June 9, 2011 in New York City. Roof Piece (1971) consists of nine dancers performing improvised movement signals to each other in a chain on various rooftops overlooking the city. This presentation marked the first full performance of the piece since 1973. (Photo by Mario Tama/Getty Images)

Photographer Andy Hall joins the thousands of fans from west Africa who have gathered for Baaba Maal's annual Blues du Fleuve festival in Senegal. Here: Dancers wait to perform on stage. (Photo by Andy Hall/The Observer)

Dancers from the School of American Ballet Chloe Ellis (R) and Amarra Hong (L) prepare for a performance at the Queens Theatre in the Queens borough of New York February 28, 2016. (Photo by Shannon Stapleton/Reuters)

Dancers take part in the Karneval der Kulturen (Carnival of Cultures) street parade of ethnic minorities in Berlin, Germany, May 15, 2016. (Photo by Hannibal Hanschke/Reuters)

Morenada dancers perform during the “Senor del Gran Poder” (Lord of Great Power) parade in La Paz, May 21, 2016. (Photo by David Mercado/Reuters)

Dancers perform during the Opening Ceremony of the Rio 2016 Olympic Games at Maracana Stadium on August 5, 2016 in Rio de Janeiro, Brazil. (Photo by Jamie Squire/Getty Images)

Dancers Daisy Kerry (R) and Alice Rathbone pose as characters from The Nutcracker, for the annual Christmas event at Chatsworth House near Bakewell in Britain November 4, 2016. (Photo by Darren Staples/Reuters)

Dancers take part in “La Vijanera”, a winter masquerade at the beginning of carnival season in Europe, in Silio, northern Spain, January 8, 2017. (Photo by Vincent West/Reuters)