Cities are under siege. Sometimes that has been literal, as with cities in Ukraine and Gaza, and sometimes it has been more metaphorical, with a human cost, as in some US cities today. In addition, many cities are dealing with something that may feel like a siege, from the brutal heatwaves that envelope cities in India and elsewhere to the loss of funding and people that affect shrinking cities in many aging nations.

Our January 2025 Editorial discussed urban capacities and constraints and the gulf between urban ideals and realities. This year has tested cities in striking, expected and unexpected ways. Many cities and the scholars who study them are struggling, in Red Queen style, just to remain roughly where they are, with little luxury to strive for ideals. Indeed, a look at 2026 conferences that feature urban research finds a subtheme, among many, of change and uncertainty. Under duress, then, what are cities doing and becoming? How should we think about, study and understand these challenges and responses?

Our December 2025 issue features several papers focused on cities, individually and collectively, struggling to find balance, address risks and be resilient. Rybski and coauthors speculate in their Comment, with examples from Germany, about how cities can balance maturation with not expanding their land use. Balancing air-quality efforts is another frontier. In their Comment, Xianmang Xu and coauthors note that China’s border cities are suffering disproportionately from health and economic burdens of poor air quality even as the country as a whole improves. In their Article, Andrew Renninger and colleagues use GPS data to show that US cities are characterized by rings of isolation around cities and pockets of segregation within them, a pattern that has strengthened since the COVID-19 pandemic. In their Article, Basu and coauthors balance typical perspectives on urban food provisioning with their focus on foraging in rivers and other blue spaces in four Indian cities, and find that these spaces especially support older women, often from the most disadvantaged groups. Urban parks have key supportive roles as well. An Article by Linus Dietz and coauthors assessed thousands of parks across 35 cities to find regional differences in such support: North American parks focus more on physical activity and European parks more on nature enjoyment, and suburban parks often lack the space and equipment for nature-based, social and cultural activities.

Indeed, other papers in this issue look generally at strategies cities can take, especially around natural resources. Supporting urbanites during heat waves is a key touted benefit of vegetation, for example. Yu Qiu and colleagues, in their Article, find that lawns provide intense bursts of cooling, whereas trees access deeper water and so provide more-moderate but prolonged relief. Complementing this, a meta-analysis Article by Wei Wang and colleagues shows, encouragingly, that nature-based solutions (especially green infrastructure) reduce daytime temperatures by more than 2 °C. Water access emerges as another critical concern. An Article by Rafael Prieto-Curiel and colleagues finds that, among 100 cities, urban sprawl reduces water access but that compact growth could provide piped water to millions more people than more-horizontal growth could. Cities often treat water and solid waste separately, but Feixiang Zan and colleagues, in their Article, find a threshold at which diverting food waste into sewage streams becomes cost effective and reduces greenhouse-gas emissions. Strikingly, Chunshui Yu and coauthors, in their Article, find associations between early-life urbanicity and age at menarche and, in turn, medial prefrontal volume and levels of agreeableness and reward dependence in adulthood.

Fortunately, even under duress, cities and urbanites are finding their way. Indeed, other papers in this issue consider such wayfinding from different angles. Looking back, Zhenhua Chen and coauthors, in their Article, find that between 1831 and 2021 in England and Wales, railway infrastructure gradually aligned with population, with railway expansion coinciding with the growth of small and mid-sized cities and growing regional connectivity. Another Article from Prieto-Curiel shows that metros help residents of European cities to find their way around and to reduce reliance on cars. The turn towards the virtual is affecting cities as well. A Review by Guodong Sun and coauthors discusses the potential of mobile-crowd data to inform the virtual-city replicas known as urban digital twins. In his World View, Haochen Shi considers the reciprocal relationship between real and virtual cities as seen through city-building video games. Looking inward is generative as well. Maria Lorono and colleagues, in their Article, use artist-produced illustrations to find characteristic variation in how urbanites imagine climate adaptation in their cities.

As cities see themselves through the various looking-glass options, the community trying to study and understand cities needs to recognize that change is inevitable, that the world today is often fantastical, that there is value in stepping through rather than just gazing at, and that we should recognize looking glasses as tools for self-understanding as well as self-deception.