A new book about the history of Paris suggests one bridge played a critical role:
The construction of a new bridge over the Seine was initiated by Henri IV’s predecessor, the last king of the Valois dynasty, Henri III, who laid the first stone in May 1578. Some early projects conceived of a very different bridge, most notably, with shops and houses lining each side. In 1587, construction was just becoming visible above the water line when life in Paris was upended by religious violence. With the city in chaos, work on the bridge ceased for more than a decade.
In April 1598, Henri IV signed the Edict of Nantes: the Wars of Religion were officially over. A month earlier, the new king had already registered documents announcing his intention to complete the bridge. Henri III had offered no justification for the project; his successor, characteristically, laid out clear goals for it. He presented the bridge as a “convenience” for the inhabitants of Paris. He also characterized it as a necessary modernization of the city’s infrastructure—Paris’ most recent bridge, the Notre-Dame bridge, was by then badly outdated and far “too narrow,” as the king remarked, to deal with traffic over the Seine, which Henri IV described as rapidly expanding because new kinds of vehicles were now sharing the bridge with those who crossed on horseback and on foot. The new bridge would be financed in a previously untested manner: The king levied a tax on every cask of wine brought into Paris. Thus, as city historian Henri Sauval, writing in the 1660s, phrased it, “the rich and drunkards” paid for this urban work.
No prior bridge had had to deal with anything like the load the New Bridge was intended to bear—most significantly, a kind of weight that in 1600 was just becoming a serious consideration: vehicular transport. Earlier cities had only had to contend with transport that was relatively small and light: carts and wagons. In the final decades of the sixteenth century, personal carriages were just beginning to be seen in cities such as London and Paris. Nevertheless, with great foresight, each of Henri IV’s documents on the Pont Neuf adds new kinds of vehicles to the list of those to be accommodated. He was thus the first ruler to struggle with what would become a perennial concern for modern urban planning: the necessity of maintaining an infrastructure capable of handling an ever greater mass of vehicles.
The New Bridge became the first celebrity monument in the history of the modern city because it was so strikingly different from earlier bridges. It was built not of wood, but of stone; it was fireproof and meant to endure—it is now in fact the oldest bridge in Paris. The Pont Neuf was the first bridge to cross the Seine in a single span. It was, moreover, most unusually long—160 toises or nearly 1,000 feet—and most unusually wide—12 toises or nearly 75 feet—far wider than any known city street.
This seems appropriate given how the word bridge is often used: it isn’t just “a structure carrying a road, path, railroad, or canal across a river, ravine, road, railroad, or other obstacle” but is often used as a verb to generally refer to connecting things. I’m thinking of the term “bridging ties” in the social networks literature referring to building relationships across networks or groups that is contrasted with “bonding ties” that tend to build up in-group connections. In this case, a bridge helped bring Paris together.
This is also a good example of the enduring effect infrastructure can have. Done well, something like a bridge can help people travel, encourage commerce, and become a landmark and gathering place. Done poorly, the project may snarl traffic, repel rather than attract people, and fall apart or be demolished to try again.