Riot security forces clash with demonstrators as a motorcycle is set on fire during a protest against Venezuelan President Nicolas Maduro's government in San Cristobal, Venezuela May 29, 2017. (Photo by Carlos Eduardo Ramirez/Reuters)

A dead body is seen on the ground after violence erupted in the Independence Square in Kiev February 20, 2014. Ukrainian protesters seized back Kiev's Independence Square in fresh clashes with riot police on Thursday that left several injured and possibly two demonstrators dead. (Photo by David Mdzinarishvili/Reuters)

Desiree Urban is painted at Columbus Circle as body-painting artists gathered to decorate nude models as part of an event featuring artist Andy Golub, Saturday, July 26, 2014, in New York. Golub says New York was the only city in the country that would allow his inaugural Bodypainting Day. (Photo by John Minchillo/AP Photo)

A protester poses for a photo in front of a burning barricade in Barcelona, Spain on February 17, 2021 as a protest following the imprisonment of rapper “Pablo Hasel” convicted to jail for glorifying terrorism and insulting Spain's former king in lyrics turns into riots for a second night. (Photo by Matthias Oesterle/ZUMA Wire/Rex Features/Shutterstock)

Women clash with police officers behind riot shields during a protest in support of Victoria Salazar, a Salvadoran woman who died after a Mexican female police officer was seen in a video kneeling on her back, in Mexico City, Mexico on April 2, 2021. (Photo by Raquel Cunha/Reuters)

Polish police in riot gear detain protesters, angry over new restrictions aimed at fighting the coronavirus pandemic, in Warsaw, Poland, Saturday, October 24, 2020. The protesters included entrepreneurs, far-right politicians, football fans and vaccine opponents. The clashes come amid rising social tensions and as new restrictions just short of a full lockdown took effect Saturday. (Photo by Czarek Sokolowski/AP Photo)

Bicycles of various bike-sharing services are seen at an urban village in smog during a polluted day in Shanghai, 2017. Rapid expansion of shared bicycle companies across China has led to massive piles of abandoned bikes as supply outstrips demand. (Photo by Aly Song/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)