Singer Madonna performs during her concert at the AccorHotels Arena in Paris, France, December 9, 2015, on her Rebel Heart Tour. (Photo by Benoit Tessier/Reuters)

Fifty years ago, as France exploded in mass protests, words scrawled on the walls of the Sorbonne summed up the revolutionary zeal of the time: “Run free, comrade, we’ve left the old world behind!”. Sexual liberation, artistic creativity and anti-capitalism were the order of the day. For those who were there, it was an unforgettable time. Here: A wounded student is transported by first-aid workers during riots on the Boulevard Saint-Michel, Paris, France on May 6, 1968. (Photo by Gökşin Sipahioğlu/SIPA Press)

Actress Athene Seyler attempts to contort her body, in a scene from the show, “Skin Deep”. (Photo by Sasha/Getty Images). Circa 1928

A new monorail service in Houston, Texas, ready for its inaugural service. (Photo by Evans/Three Lions/Getty Images). Circa 1950

A British woman plays a piano designed especially for people who are confined to bed. Date: 1935. (Photo by Mary Evans Picture Library/Caters News)

A model walks the runway at the Elie Saab fashion show during Paris Fashion Week on March 9, 2011 in Paris, France.

A model presents a creation by French designer Barbara Bui as part of her Spring/Summer 2016 women's ready-to-wear collection during Fashion Week in Paris, France, October 1, 2015. (Photo by Charles Platiau/Reuters)