Like our cities, our research and opinion on cities reflect us. What do they say? For one, our understanding suggests a tension between capacities and constraints. Cities empower and circumscribe, and so does our study of them. We look back briefly through our first year of Nature Cities and review our sense of the landscape of urban research, in service of then looking forwards.

One thing we notice in looking back is the echo of familiar themes in urban research broadly and that we have highlighted and encouraged: local insights matter, cities are unequal, urban greening moderates climate, cities house more than people, scale is inherently important, interdisciplinary research is generative and so on. These are big insights that deeply inform our understanding and study of cities. Yet they are also, by now, twice-told tales. Paper after paper has expanded on the original insights. Taking a road twice or more does not necessarily mean the journeys are tedious or uncourageous, as the more we understand about, for example, specific aspects of inequality in cities, the more firmly we recognize essential qualities of urban inequality and the more we understand about it holistically. But the elaboration of known relationships suggests the urban research community has new avenues to explore, and more to say. What will that be?

Just as there are tensions in the everchanging nature of cities, there are tensions in what cities and urban research have done and what they can do. Cities, for instance, make efforts to control pollution, to enforce equitable policies, to efficiently develop land and so on, but the unions between their ideals and their efforts are rarely perfect. Cities must work with economic and political realities, and scholarly incentives and publishing constraints limit efforts of those studying cities.

What do those constraints suggest? Are they just about capacity, including resources? Or about timing, such as the lag between implementation and the nature of changing targets? Is it because cities are reflection of us1, and we are not platonic ideals? What can we learn from exploring these spaces and places? Nature Cities welcomes research and opinion that explore these shortfalls in addition to exposing them. We ask out of curiosity and concern, not with an expected answer in mind.

Much of the content in our January 2025 issue grapples with such gulfs. Isabelle Anguelovski’s Perspective focuses on the gulf between unequal effects of heat in cities and apolitical heat-response strategies. Hong Yang’s World View considers the gulf between the promise of autonomous taxis and their current incarnation. Mahir Yazar’s Article explores the gulf between policy efforts to incorporate climate equity and the lack of procedural justice in decision-making. Cynthia Chen’s Article finds a gulf between the potential for community resilience, as from disasters, and the reality from place-based peer-to-peer resource sharing. Yiqi Tang’s Article finds a gulf between PM2.5 (particulate matter of 2.5 μm diameter or less) pollution in Chinese urban areas with new air-pollution monitoring stations and those without, and in associated welfare consequences. Lifeng Shi’s Article focuses on the gulf between housing supply and demand in a sample of 108 Chinese cities and finds a growing disconnect, especially in small cities. Lexuan Zhong’s Article also considers a gulf, here between optimal and suboptimal paths for deploying renewable-based distributed energy systems in residential communities to decarbonize cities. Katie Meehan’s Article finds a widening gap in water access, one that disproportionately affects households of color in 12 of the 15 largest cities in the USA. And Farrukh Baig’s I and the City explores the space between Changsha’s traditional spirit and its future-oriented ambitions around transportation.

Other content considers the ways cities structure and filter options. Satish Ukkusuri’s Article finds that most cities in the USA, Canada, the UK and France do not experience migration shocks but that small cities can experience them as well, mostly owing to population movement from larger ones. Arzi Adbi’s Comment argues for studying and mitigating noise pollution to improve learning by urban youth in developing economies. Tyler Valiquette’s World View suggests a model from Bogotá for providing care and community for queer urban migrants. Finally, Kun Song’s Article finds that plants that colonize cities without being planted are likely to be those that disperse their seeds without help as well.

A raft of articles have noted the need for cities to take up the baton from regional, national and international governments, whether on tackling climate change or changing social forces. So, understanding the gulfs between the potential of cities and urban research and the realities both face is especially urgent. We hope you will help us to shed light on these shadowy spaces.