Earlier this month, while China's leaders were staging a grandiose celebration of their revolution's 40th birthday, thousands of somber Hong Kong residents gathered for a dreary commemoration of their own. Far from the fireworks display in Beijing, Hong Kongers huddled in a rainstorm near the bronze statue of Queen Victoria, singing patriotic songs and listening to mournful poems dedicated to those who died in Tiananmen Square.

On the twilight of the Iranian Revolution.

Fidel Castro, the fiery apostle of revolution who brought the Cold War to the Western Hemisphere in 1959 and then defied the United States for nearly half a century as Cuba’s maximum leader, bedeviling 11 American presidents and briefly pushing the world to the brink of nuclear war, died on Friday. He was 90.

A father’s search for meaning and justice five years after his son was killed during the Tahrir Square uprising.

An ethnography.

A portrait of Czech President Václav Havel as he left office.

“It’s striking that for all the talk about polarization in the US, the Tea Party Movement and Occupy Wall Street are entirely non-violent. Overseas, no one expected the Arab Spring protests to be as nonviolent as they were,” Pinker wrote in an email. The threat of overwhelming reprisal from authorities may have brought some peace to seventeenth- and eighteenth-century England, but Pinker also pointed to research that, today, “nonviolent protest movements achieve their aims far more often than violent ones.” Still, the story of violence’s decline contains much violence, and America is no exception.

He arrived in Bolivia in November 1966, disguised as a Uruguayan businessman. After desertions, drownings, and difficulty contacting their support group in La Paz, his small troop was surrounded the following October. The inside story of how they were found and destroyed.

The sudden, bloody transformation of normal citizens into rebels.

On Colonel Muammar Qaddafi, “the permanent revolutionary,” and his son Seif.

What Egypt learned from the students who overthrew Milosevic. “The Serbs are not the usual highly paid consultants in suits from wealthy countries; they look more like, well, cocky students. They bring a cowboy swagger. They radiate success. Everyone they teach wants to do what the Serbs did.”

A primer on Egypt’s political landscape.