A swelling tide of visitors is overwhelming many of the world’s most celebrated historic cities, straining their infrastructure, displacing their residents, and prompting a reconsideration of how destinations manage the tourism that sustains them economically yet threatens to erode the very qualities that draw people to them. The phenomenon, increasingly described as overtourism, has become a defining challenge for places whose appeal has outpaced their capacity to absorb the crowds it attracts.

The growth in tourism reflects broad and largely positive trends, including rising prosperity in many parts of the world, the falling cost of travel, and the ease with which trips can be planned and booked. More people than ever can afford to travel, and the most famous destinations, concentrated in a limited number of iconic cities and sites, draw a disproportionate share of them. The result is that places designed for far smaller populations find themselves inundated, sometimes by visitors who outnumber residents many times over during peak periods.

The strains are manifold. Infrastructure built for a certain scale of use, from transportation to water and waste systems, buckles under the weight of crowds. Historic sites suffer wear from the sheer volume of visitors. Streets and squares become congested to the point where daily life for residents grows difficult. The character of neighborhoods shifts as shops and services oriented toward residents give way to those serving tourists, hollowing out the local life that made the place distinctive in the first place.

The effect on housing has been particularly acute. The conversion of homes into short-term rentals for visitors reduces the supply available to residents and raises prices, contributing to the displacement of locals from city centers. As residents leave, the communities that animate a city can thin, leaving districts that function as stage sets for visitors rather than as living neighborhoods. The irony is sharp: the authenticity that draws tourists is undermined by the volume of tourism itself.

The economic dependence on tourism complicates any response. For many destinations, tourism is a vital source of income and employment, and measures to limit it risk harming the businesses and workers who depend on visitors. This dependence creates a tension between the desire to manage the crowds and the fear of damaging an economic mainstay, and it makes the politics of restricting tourism fraught, pitting the interests of those who profit from visitors against those who bear the costs of overcrowding.

Cities have experimented with a range of measures to manage the pressure. Some have introduced fees intended to moderate demand or fund the upkeep that tourism necessitates. Others have restricted the largest sources of crowds, limited short-term rentals to protect housing, or sought to disperse visitors across time and space to relieve the most congested points. The effectiveness of these measures varies, and each involves trade-offs between managing the crowds and preserving the access and economic benefits that tourism provides.

The challenge reflects a broader tension in a world where the capacity to travel has expanded faster than the capacity of celebrated places to absorb the resulting crowds. The most famous destinations face the prospect that their popularity, left unmanaged, could degrade the experiences and erode the communities that made them famous. Finding a balance that sustains the economic benefits of tourism while preserving the livability and character of host cities has become a pressing question for destinations around the world, and one without easy answers.