MEXICO CITY, Mexico—Thursday was an annual holiday in Mexico, the anniversary of the start of the Mexican Revolution against the dictator Porfirio Díaz in 1911. The giant faces of yesteryear’s heroes, Pancho Villa and Emiliano Zapata, were part of a lighted holiday display that gazed down on the Zócalo, the main plaza in downtown Mexico City. But the usual military parade and reenactment of scenes from the revolution were canceled amid talk that a new revolution is brewing.

Public indignation continues to run high after the murders on September 26 of three students from a rural teachers’ college in southern Mexico and the abduction of forty-three of their classmates by police accused of working in league with a drug cartel. On Wednesday, at a rally in the nearby city of Cuernavaca, parents of the missing students declared that the anniversary of the Mexican Revolution was “the day that we will make our revolution if that is the way the President Enrique Peña Nieto wants it; we are going to march because we want our children found.”

Nearly two full months have passed since the student massacre that took place in the city of Iguala, Guerrero. In spite of the dozens of arrests in the case, including more than 50 police officers, the mayor and first lady of Iguala, the investigators appear to be no closer to discovering what happened to the missing students. Adding to the tension, President Peña Nieto made televised comments twice this week about his willingness to crack down on violent elements—among the protestors.

On Sunday, freshly returned from a diplomatic trip to China, Peña Nieto reminded TV viewers that “the state is equipped for the use of force.” Two days later, he accused certain unspecified elements of the protest movement of capitalizing on the grief of the victims’ families to commit acts of violence that deliberately “destabilize” his government. Allies of the president, from the governor of Mexico State to Mexican congressional leaders and the president of The Business Leadership Council, have followed suit.

Meanwhile in the state of Guerrero, where the murders and disappearances took place and where emotions tied to the case run highest, 300 members of a teachers’ union protested by padlocking the gates of the state supreme court. In Acapulco, the teachers commandeered 10 buses and drove them to the office of the superintendent of schools, which has been under their control for the past 39 days. The buses were to be used to transport union members to the protests in Mexico City.

Omar Garcia, a student at Ayotzinapa and spokesman for the student caravan, said at a rally that “the Mexican State no longer exists for us, and all of its institutions to us are worth nothing” because, he said, “they all reproduce the same evils.”

Reforma, a popular daily, reported that a special force of 5,000 riot police was being assigned to the march in the afternoon and to an act of civil disobedience in the morning, where students were going to attempt to block all traffic from reaching Mexico City International Airport. Police sources informed Reforma that both action are considered “high risk” and ripe for “anarchist infiltration.”

The airport blockade didn’t materialize. The night before the march, the student assembly that’s supposed to be running the protests voted withdrew its support. But a hard core of students pushed ahead without the endorsement of the larger council.

At 10:00 a.m. Thursday, federal police at the airport swarmed a group of 14 teenagers, black flags still rolled up in their hands. A group of bemused tourists waiting for taxis kept their luggage close by as a about 50 reporters rushed past in pursuit of the teens, who hurried away on a public bus.

At 11:00 a.m., a group of 40 young people, mostly teenagers, rallied at a subway station about a mile from the airport. They wore t-shirts wrapped around their heads and covering their faces, and many of them wore sunglasses to further conceal their identity. Someone wore a Guy Fawkes mask under a hoodie. They could be overheard saying they were students from the Autonomous University of Mexico City, and the Autonomous Metropolitan University of Azcapatzalco, and Iztapalapa, though most of them looked of high-school age.

The protesters blocked the passage of traffic on a freeway called Circuito Interior and for several jubilant minutes shouted chants and went to scrawling slogans in graffiti on the concrete dividers: “Blow out the candles, light the barricades.” “I hate the State.” “All bullets shall be returned.”

A handful of them could be seen brandishing tree branches and table legs as weapons. A detachment of riot police blocked their way to the airport, and the protesters altered their route. For the most part passing motorists honked support, even raising their fists in solidarity in a few instances. One trucker did shout an obscenity, and a musclebound mechanic told them to go and do something useful like study.

They made one last charge for the airport, and when the riot police blocked them again a melee ensued. A few molotov cocktails were flung. The windows of a patrol car were smashed. A hundred of them ended up surrounded and some of them were arrested.

In the months that have elapsed since Iguala, college student activists in Mexico City have come to adopt the view that the fate of their peers in Guerrero is part of a broader attack on students and education in Mexico. Two days before the protest, police in Mexico City shot and wounded a student outside the Che Guevara Auditorium on the campus of the National Autonomous University of Mexico, where the cops cannot enter. At the National Polytechnical Institute, students have been on strike all year in protest against a federal education reform that reduces a prestigious four-year engineering degree to a two-year associate’s degree.

In the center of the capital, the march on Thursday was divided into three feeder marches, and the main rally point for the student contingents was two and a half miles north of the Zócalo in the Tlaltelolco Plaza. The students had control of the turnstiles in the subway station. “Nobody pays!” they were shouting into a bullhorn, and a transit cop stood by as men and women in work clothes crawled under a turnstile one after another.

Outside in the plaza there was the explosions of fireworks, the whiff of marijuana, the beat of jembe drums. As students from the various universities arrived they whooped and cheered and jumped up and down like concertgoers, shouting that whoever wasn’t jumping was the president.

They filed past hoisting homemade flags, university flags, Mexican flags, flags that said “Ayotzi Vive.” Along the path to the rally students held signs like the one that read, “This is the cry of a people demanding freedom.”

Viewed from the height of a pedestrian overpass, the march extended for several blocks, with more and more students tailing onto the end.

The enthusiasm of the rear contrasted with the solemnity of the front, where the parents of the missing Ayotzinapa students were in the lead. Each of the three feeder marches was named after one of the three students killed in Iguala, and this one’s name was Julio Cesar Mondragon. The parade marshals for the lead contingent of parents were campesinos from Atenco in their straw hats, brandishing machetes with political slogans drawn on the blades in red ink.

On nearing the Zócalo, the contingents mixed together. The turnout was massive, more than 100,000 people.

A call from the stage for President Peña Nieto to resign drew the loudest applause. The Zócalo is one of the largest public squares in the world and the sound system for the rally could reach only a fraction of the crowd. The speeches washed over the masses and were absorbed. More noise came from the crowd itself, which chanted ceaselessly, different chants coming from different areas in the mass, one blending into the next. People could be heard complaining they couldn’t hear a thing but for an hour no one seemed to leave.

Somebody built an effigy of President Peña Nieto that was 20 feet high. He was in a suit with a clown nose and blood on his hands. It was torched in the middle of the Zócalo.

The elite presidential guard stood alert in front of the Mexican National Palace where the president keeps his main office. Near the end of the rally, someone placed a giant funeral wreath on one of the metal dividers that stood between the protesters and the palace door. The sign beside the wreath accused the government of “narco-politics” and “state terror.”

At a rally only a month ago demands for the president to resign were a kind of radical flourish that drew cheers from the usual suspects in the crowd. Thursday night, nearly two months removed from the events in Iguala, several thousand people amassed in front of the National Palace and shouted in unison for Peña Nieto to resign. The faces of Villa and Zapata looked on from the opposite end of the square.

At the conclusion of the rally, the crowd lingered for an hour or more in the Zócalo and bits of the vanguard in front the National Palace began to jeer at the presidential guard and to seize hold of the metal barriers and attempt to uproot them from their moldings. Someone lit a firework and tossed it in the direction of the presidential guard and it went off with a loud bang that altered the atmosphere, making the crowd suddenly more combative. More fireworks followed the first, and the metal barriers rattled. Shouts came from the rear of the crowd for “no violence,” shouts that went largely unheeded. A Molotov cocktail tumbled in an arc overhead and erupted briefly in a blaze. There were a few more of those. Some of the marchers began to chant at the anarchists, reminding them that the movement is bigger than them.

Green laser pointers shined in the faces of men in uniforms looking down from the roof of the National Palace. The crowd shouted again for the president to resign and again there were more explosions from fireworks, and more shouts from the rear against the use of violence. By now, there was a cloud of smoke in front of the palace. People were singing the national anthem as the whole front of the National Palace was obscured by a smoke cloud.

Riot police eventually converged from the flanks, hundreds at first, then hundreds more, with shields and batons. Clouds of tear gas filled the air. The riot police advanced on the crowd and the crowd gave some ground but did not retreat. As the police and protesters continued their stand off, the protesters began counting at the top of their voices in unison from one to forty-three. It was the night’s most impressive display of unity.

Then the crowd dispersed and a few of the stragglers were arrested. Villa and Zapata looked on, smiling their papier mache smiles, sure they had seen something like this before.