Students wearing mask hold hands to surround the St. Stephen's Girls' College in Hong Kong, Monday, September 9, 2019. Thousands of demonstrators in Hong Kong urged President Donald Trump to “liberate” the semiautonomous Chinese territory during a peaceful march to the U.S. Consulate on Sunday, but violence broke out later in the business and retail district as police fired tear gas after protesters vandalized subway stations, set fires and blocked traffic. (Photo by Kin Cheung/AP Photo)

Animal rights activists from the group “Animal Equality” are covered with plastic sheets to represent meat packaging as they stage a protest during “Day Without Meat” event in Barcelona, Spain, on March 20, 2013. (Photo by Lluis Gene/AFP Photo)

Teams face off in the Cartier Elephant Polo Cup November 18, 2006 in Jaipur, in the Indin state of Rajasthan. Cartier hosted the event which was held to highlight the plight of the dwindling numbers of Asian elephants. Indian and international celebrities flew in the India's “Pink City” for the high society event held by the global watch and jewelry giant. The animal rights organization, People for the Ethical Treatment of Animals, “PETA” had planned to protest the match, saying that elephants should not be used for sport. Elephants in Jaipur are commonly used for carrying tourists at historic sites. (Photo by John Moore/Getty Images)

Supporters of Ratko Mladic wave flags with his picture and reading in Serbian “Serbian hero” during a rally organized by the ultra nationalist Serbian Radical Party in front of the Parliament building on May 29, 2011 in Belgrade, Serbia. Some 7,000 supporters of the former Bosnian Serb army chief Ratko Mladic, who was arrested on Thursday in a village in Serbia after 16 years on the run, took to the streets of Belgrade, to hear speeches and protest Mladic's arrest. Mladic, who is facing extradition to the The Hague, is accused of war crimes, including the 1995 massacre of 7,500 Muslin men and boys in Srebrenica. (Photo by Srdjan Stevanovic/Getty Images)

A boy dances as he and others participate during the 4th Delhi Queer Pride 2011 March on November 27, 2011 in New Delhi, India. India's Lesbian, Gay, Bisexual and Transgender (LGBT) community celebrated the 4th Delhi Queer Pride March with a parade through the streets of Delhi. People gathered to protest violence, harassment and discrimination faced by the LGBT community in India. (Photo by Daniel Berehulak/Getty Images)

A demonstrator is detained by police officers during clashes in downtown Barcelona, Spain, Friday, October 30, 2020. Clashes have erupted in a central Barcelona square between anti-riot police and hundreds who had gathered to protest the mandatory closure of bars, restaurants and other businesses in the latest effort to rein in on coronavirus outbreaks. (Photo by Joan Mateu/AP Photo)

Law enforcement officers detain a man during a rally in support of jailed Russian opposition leader Alexei Navalny in Moscow, Russia on January 31, 2021. Thousands of people have taken to the streets across Russia to demand the release of jailed opposition leader Alexei Navalny, keeping up the wave of nationwide protests that have rattled the Kremlin. Hundreds have been detained by police. (Photo by Maxim Shemetov/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)