The history of revolutions has gone global. Historians today can hardly avoid a powerful sense of how the worldwide flow of capital, goods, people, and ideas shapes local circumstances. Guided by this understanding, they have now composed a significant body of work showing how similar forces in the past could put states and empires under massive strain, resulting in potentially revolutionary crises. Histories of events like the French and Russian revolutions have always taken their global dimensions into account, but recent work has insisted on the paramount importance of these dimensions. Justin du Rivage’s newly published Revolution Against Empire, for example, casts the American Revolution as the result of a debate within a globe-spanning British Empire as to what form the empire should take. The French historian Pierre Serna has proposed seeing the French Revolution as just one chapter in a long struggle waged throughout the world between elites and the peoples they subjugated, both in overseas colonies and in homegrown “internal colonies.”

Mike Rapport’s lucid, engaging, and evocatively written The Unruly City: Paris, London, and New York in the Age of Revolution seems at first sight like another contribution to this global turn. The three cities were all important nodes of global exchange with diverse, cosmopolitan populations, and the book devotes significant space to the connections between them and their respective countries. But The Unruly City isn’t really a global history, at least in the new sense, for it pays relatively little attention to the cities’ positions in global networks of exchange. Instead, Rapport’s book demonstrates how attention to the specific geography and social forces of a city can illuminate a critical question about which the new global history has little to say: Why do people in some places—but not others—become radicalized, driving revolutions into previously uncharted territory?

Analyses of ocean-spanning empires and trade networks can do much to explain the political, economic, and social stresses tied to globalization that can lead to revolutions breaking out in the first place. However, to understand events like the American and French revolutions, one must look not simply at their origins in the wider world, but also at how particular environments—above all, urban ones—could become crucibles of intense and rapid political change. Both revolutions quickly took on a life of their own and brought about events that few, if any, people had predicted or could even have imagined at the start. The American Revolution rejected monarchy, shook the social structures of the new state, and tied its legitimacy to the sweeping principles proclaimed in the Declaration of Independence. The French Revolution went even further in its challenge to the reigning social order: In addition to overthrowing a monarchy, it brought about the execution of a king, the flourishing of utopian visions of human improvement, and an attempt to abolish Christianity on French soil. Great Britain also seemed for a time to be fostering the development of a volatile, potentially revolutionary politics, but there the government and social elites ultimately managed to prevent an explosion.

One reason that global history has difficulty with radicalization has to do with the scale on which it operates. Global history is, by definition, large-scale: Even works that use a single individual to elucidate global processes, like Linda Colley’s The Ordeal of Elizabeth Marsh, still cover huge swaths of the world. Radicalization, by contrast, tends to take place in relatively small, contained spaces, where like-minded people can exchange news and ideas, reinforce their shared passions, and magnify their outrage at their opponents. Today, we can experience this phenomenon virtually, through social media; those living in the mid-19th century could experience it within the spaces of intensive political socialization provided by revolutionary political parties. But before the existence of such parties, radicalization generally required either an accelerated circulation of printed material, large-scale face-to-face contact, or, preferably, both. And by far the easiest place to find these things was in cities, which offered more than just population density: They had cafés, taverns, clubs, and libraries where patrons could discuss political issues and read newspapers and pamphlets. They had squares and parks where crowds could gather in large numbers, and they had long traditions of popular unrest and mobilization. They also had—especially in capital cities—government buildings and monuments that provided ready targets for these crowds, and whose capture had both practical and deeply symbolic meaning. Cities, in other words, contained a mix of social and cultural elements that could turn volatile, even explosive, with terrifying speed and push dramatically outward the limits of what was politically imaginable.

Revolutionary Paris offers a classic example of why this was the case, and Rapport, a French-history scholar by training, deals with it well. In 1789, at the start of the French Revolution, Paris had a population of about 650,000, crammed into an area less than a third the size of the modern city, which meant that, despite the lack of high-rise apartment blocks, it had only a slightly lower population density than it has today. Paris was crowded, disorderly, loud, and, given the lack of anything close to an adequate sewer system, unbelievably odoriferous. “Why they tell me I am no judge, for that I have not seen it yet,” Rapport quotes Abigail Adams as writing to her niece in 1784. “One thing, I know, and that is that I have smelt it…. It is the very dirtiest place I ever saw.”

At several points in Paris’s tumultuous history, popular insurrections had forced the king to flee the city. And while Paris was not the capital of France at the start of 1789 (Louis XIV and his ministers had decamped to Versailles a century earlier), it still was home to much of the government bureaucracy and also rich in the symbols of royal rule. When crowds stormed the fortress and prison known as the Bastille on July 14, they did not overthrow Louis XVI or seize control of his government. But given the Bastille’s fearsome reputation as a symbol of royal despotism (even if, by 1789, there were just seven prisoners left in it, including two lunatics), its fall inspired revolutionary uprisings across the country, and Louis quickly acquiesced to major revolutionary reforms.

During the revolution, scores of newspapers were printed in Paris, many of them on a daily basis, flooding the city. The major sites of political activity all lay within little more than two miles of one another. When church bells sounded an alarm, large crowds could assemble within minutes. The great chronicler of 18th-century Parisian life, Louis-Sébastien Mercier (whom Rapport doesn’t quote nearly enough), compared the revolutionary metropolis to “a city under siege; almost every day there were the drumbeats…the shouts of the militants, gunshots, the fears of some, the ferocious joy of others, and predictions of the most terrible catastrophes.” It was an exhausting experience: “How we have aged over the past eight years,” Mercier wrote in 1797. Time and again, it was armed insurrection by Parisian militants that drove the French Revolution to the left.

Soon after the fall of the Bastille, Rapport notes, one small electoral district on the Left Bank became an especially febrile hub of radicalism. This was the Cordeliers district, named for a local convent and located around what is now the square of the Odéon on the Boulevard Saint-Germain. Three of the revolution’s most famous firebrands lived there: the great orator Georges Danton and the journalist-politicians Camille Desmoulins and Jean-Paul Marat. Meetings of the district assembly were loud and raucous: Members denounced supposed counterrevolutionary conspiracies and impelled one another to ever more extreme stances. Desmoulins called the Cordeliers district a “little Sparta” and claimed that he knew all its residents by sight. When moderates in the national government redrew Paris’s internal borders in 1790 and restricted voting to the well-off, the radicals of the Cordeliers formed a club in the neighborhood to continue their militant activities, opening its doors to both bourgeois and plebeian members.

Earlier than anyone else in France, members of the club called for a democratic government based on universal male suffrage, for the replacement of the monarchy by a republic, and for a war of liberation against the rest of Europe. When a young woman stabbed the fanatical Marat to death in 1793, club members orchestrated elaborate funeral ceremonies and, according to one account, suspended an agate urn containing his heart from the ceiling of their meeting hall. A club member declaimed: “O heart of Jesus, O heart of Marat…you have the same right to our homage…. Their Jesus was but a prophet but Marat is a god.” Only four years before, such a ceremony would have been unimaginable in a country where the Catholic Church still possessed immense land and power and at least the nominal allegiance of nearly the entire population. The intensive radicalization illustrated by the ceremony could only have happened in a place like Paris.

London and New York didn’t experience anything like this degree of radicalization during the Age of Revolution, but both served as crucibles of intense political activity in their own right. London’s 1 million inhabitants (as of 1800) were spread over a much larger area than those of Paris, but much of its political activity took place within the square mile of the City (then, as now, the financial district), which had its own government and police forces. In the 1760s, the City provided the base for the radical politician John Wilkes, who pushed for an expansion of the franchise (then largely limited to well-off men) and denounced the supposedly despotic government of George III. “Rakish, lanky, cross-eyed, jagged-toothed,” in Rapport’s description, Wilkes had a powerfully charismatic appeal for ordinary Londoners, who printed his image, and the slogan “Wilkes and Liberty,” on broadsheets, crockery, and handkerchiefs and named their children after him. (Many years later, the actor Junius Brutus Booth continued the tradition, naming his American-born son John Wilkes Booth.) He was also reported on incessantly in the city’s many daily newspapers.

Even as Wilkes sat in the King’s Bench Prison on charges of seditious libel, the voters of Middlesex, a county that included part of London, repeatedly elected him to Parliament; each time, the House of Commons quashed the results. St. George’s Fields, which today include the site of Waterloo Station, became the chosen gathering place for “Wilkite” crowds, and during a riot on May 10, 1768, soldiers opened fire on them in what would become Britain’s most notorious massacre in that century. Like the Boston Massacre, which took place two years later, it could easily have served as a prelude to revolution.

But London radicalism ended up taking a very different course from its French and American cousins’. As Rapport notes, the crucial turning point came in the late spring of 1780—and again, the inviting open space of St. George’s Fields played a catalytic role. On June 2, a crowd of some 60,000 people gathered there. This time, they were demanding not freedom for Wilkes or an expansion of the franchise; instead, they were protesting a set of parliamentary reforms that sought to ease the official persecution of Roman Catholics in Britain. Led by Lord George Gordon, a Scottish peer otherwise well-disposed to political reform, the sectarian Protestant crowds marched from St. George’s Fields to Parliament, and there the protests turned violent. A series of anti-Catholic riots followed, lasting six days, spreading over much of London and taking at least 285 lives. Some of the rioters burned to death after they invaded a Catholic-owned distillery where 120,000 gallons of gin exploded, destroying some 20 houses as well as the distillery building. “Streaks of blue liquid flame ran over the paving stones and down the gutters and gathered in fiery pools,” Rapport writes.

Many observers blamed the Gordon riots on the earlier reform movement. Edmund Burke, with his signature vituperative eloquence, wrote of “much intestine heat” and “a dreadful fermentation. Wild and savage insurrection quitted the woods, and prowled about our streets in the name of reform.” But, in fact, most middle-class Wilkites looked on with horror at the rioters’ violence and attacks on property. Wilkes himself, now a London alderman, took personal command of armed patrols and helped defend the Bank of England. In his diary, he recorded: “Fired 6 or 7 times on the rioters…killed two rioters directly opposite to the great gate of the Bank; several others in Pig Street and Cheapside.” As Rapport perceptively observes, in London the events of 1780 badly fractured the sort of connection that the Cordeliers in Paris was able to nourish a few years later between plebeian crowds and middle-class radicals.

New York, with a population of about 25,000 in 1776—less than one-thirtieth the size of London at the time—offers a very different case from the two European cities. Its role as a nursery of unruly revolutionary radicalism was also limited by the fact that soon after the proclamation of American independence, the British Army dealt George Washington his worst defeat ever in New York and then occupied the city until the end of the Revolutionary War. Philadelphia, a more important American city at the time and the site of more extensive radical political activity, might have made a better choice for Rapport.

Even so, the denizens of New York did experience their own version of political radicalization. Here too, as Rapport notes, particular spaces took on outsize symbolic and practical importance. He singles out the Common, a large open area on the site of today’s City Hall Park, close to what was then New York’s northern edge. In 1766, after the British Parliament had repealed the much-hated stamp tax, a militant group known as the Sons of Liberty celebrated the event by dragging an old ship’s mast from the docks and planting it in the Common, then decorating it with slogans. It soon became known as the Liberty Pole. A few months later, angry British soldiers hacked it down. Over the next year, two more Liberty Poles suffered the same fate, until the Sons put one up with an iron-plated base and a permanent watch. But on January 16, 1770, following new colonial protests against British policies, a group of soldiers stole by the guards in the early-morning hours, drilled a hole in the pole, filled it with gunpowder, and blew it up. That incident provoked what New Yorkers long remembered as the Battle of Golden Hill, in which soldiers with drawn bayonets fought angry rioters. On February 6, 1770, a crowd of thousands applauded as a team of horses dragged yet another set of masts from the shipyards to the Common. The result was the most impressive Liberty Pole yet, standing 68 feet high, anchored 12 feet into the ground, and protected along two-thirds of its height by iron casing.

The duel between the Sons of Liberty and the soldiers, comic as it may seem in retrospect, played a crucial role in radicalizing the ordinary people of New York, giving them an object lesson in the importance of political symbolism. Not coincidentally, six years after the last Liberty Pole went up, the Common became the place where an aide to Washington read the Declaration of Independence to New Yorkers, with Washington himself present. No sooner had the reading concluded than crowds of New Yorkers and Continental Army soldiers hurried a mile down Broadway to Bowling Green, where they tore down a two-ton statue of George III on horseback—the lead would be melted into bullets. Even a decade earlier, such an action would have struck most New Yorkers as near sacrilege.

As Rapport notes, conflicts like these resonated far beyond the borders of New York, Paris, and London, threading these revolutionary cities together. Following the example of Liberty Poles and Liberty Trees in the United States, a virtual forest of liberty sprang up across revolutionary France. John Wilkes was a hero in New York as well as London, and clubs like the Cordeliers had imitations in both cities. In June 1793, when the French ship Embuscade arrived in New York Harbor festooned with revolutionary slogans, a large crowd marched down to the waterfront to greet it singing “La Marseillaise.” Although it would be an exaggeration to speak of a “radical Internationale” in the late 18th century, networks of revolutionaries certainly did exist, and the printing press, in this golden age of pamphleteering and political journalism, made the spread of ideas between these revolutionary cities all the easier.

But while the networks and the newspapers could spread the word of radical politics, they could not, by themselves, generate radicalization. For ordinary people in these cities to adopt political positions thoroughly at odds with what they themselves had believed only a few years before—to revolt against legitimate sovereigns, social hierarchies, and even established religions—they needed more than just to hear about other people doing the same thing somewhere else. They needed the visceral, intense experience of sustained political involvement, day after day—marching, shouting, arguing, fighting, and sometimes risking their lives. This is what 18th-century cities could provide: It was in the hothouse of urban politics—on the scale of streets, not oceans—that the Age of Revolution turned truly revolutionary, and that the crises of empires could be translated into a new and audacious promise of human liberation. However much the global turn in history can add to our understanding of this period, we should not lose sight of this fundamental point. And as examples as different as the Occupy movement and Kiev’s Euromaidan should remind us, even in this age of social media and sophisticated political-party operations, urban environments still possess an unsurpassed ability to foster radical political change.