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)

“The McDonnell Douglas KC-10 Extender is an air-to-air tanker aircraft in service with the United States Air Force derived from the civilian DC-10-30 airliner. The KC-10 was the second consecutive McDonnell Douglas transport aircraft to be selected by the US Air Force following the C-9 Nightingale. The similar KDC-10 is in service with the Royal Netherlands Air Force.”

Photo: A B-52G Stratofortress aircraft takes off with another B-52G close behind. Three cells of six B-52 and KC-10 Extender aircraft will takeoff seconds apart under combat conditions during the minimum interval takeoff exercise. The exercise is a part of an operational readiness inspection by the Strategic Air Command Inspector General Team. (Photo by USAF). 1998

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

Roma people are seen in a Romani camp installed along La Petite Ceinture, an abandoned railroad line, in Paris, France, February 2, 2016. More than 350 Roma people, who have been living here since the last summer, face eviction from the makeshift camp this week. (Photo by Jacky Naegelen/Reuters)

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)

A model wears a creation for Vivienne Westwood's Spring-Summer 2016 ready-to-wear fashion collection, presented during the Paris Fashion Week in Paris, Saturday October 3, 2015. (Photo by Francois Mori/AP Photo)

A candle burns during a vigil in Aotea Square to remember victims of the Paris attacks on November 14, 2015 in Auckland, New Zealand. According to reports, over 150 people were killed in a series of bombings and shootings across Paris, including at a soccer game at the Stade de France and a concert at the Bataclan theater. (Photo by Hannah Peters/Getty Images)