Line, the foundation of all drawings, conveys shape, movement, structure and emotion. In urban landscapes, lines transcend their aesthetic roots and evolve into a critical lens that empowers researchers to uncover hidden inequities in city life. These urban lines, whether tangible (such as grid connections) or intangible (such as spatial accessibility) link households to critical resources — food, healthcare and electricity — and shape the rhythm of our urban experiences.

Long and colleagues’ Article reveals the pivotal role of railway lines in Tokyo’s culinary landscape, by using restaurant data to highlight how up to 9 million daily passengers encounter unsustainable dining environments. In Guinea’s Grand Conakry conurbation, Grovogui and colleagues’ Article examines spatial accessibility for women of childbearing age who seek childbirth care, and uncovers stark disparities. Wealthier residents live closer to both public and private facilities, whereas poorer communities in older, central neighborhoods primarily depend on public hospitals. In Kampala, Uganda, Kersey and colleagues’ Article tells a similar tale. We see electrical grid lines flowing through the city, yet they fail to deliver the promised light of ‘modern energy’ to the most vulnerable communities and leave the shadows of inequity starkly visible.

Color, another fundamental element of art, further enables artists to portray the world as they perceive it. Just as time can fade the brilliance of pigments on aged canvases, rapid urbanization and industrialization threaten the hues of urban spaces, from the greens and blues of vegetation and sky to the colors of facades and entire neighborhoods. Preserving this vivid palette demands ingenuity and resolve from urban planners, policymakers, activists, citizens and artists, as the challenges are as layered as the cities themselves.

Urban greening has been a central topic lately in urban research and in Nature Cities. Eisenman’s Q&A enriches this dialogue with a broad historical perspective, which emphasizes that urban greening itself is not the goal but rather a means to create more livable, equitable and sustainable cities. As this dialogue progresses, Zhang and colleagues’ Article quantifies urban tree coverage across major Chinese cities and recognizes successful greening efforts, while drawing attention to disparities that favor certain megacities. Shifting our gaze, blue becomes a metaphor for clean air — essential for human health and well-being. However, Zhao and colleagues’ Article highlights a shrinking window of opportunity for Chinese cities to implement short-term air-pollution controls during major events such as the Shanghai World Expo (2010), which emphasizes the need for enhanced targeting of short-term measures to support long-term policy design. Beyond the tangible, the colors of a city seep into its cultural and emotional essence, and breathe life into its identity. Cao and colleagues’ Article examines the chromatic reconstruction of Singapore’s heritage buildings over 40 years and highlights an iconic yet evolving geography of color within the city. Yin’s I and the City intertwines personal memories with the fading legacy of the Haizhou Mine, capturing the soul of Fuxin — a city defined by the enduring color of coal.

Scale, a concept that is deeply rooted in art, unlocks new perspectives in urban studies. Artistic manipulation of scale juxtaposes the intimate and the expansive, a concept that finds a parallel in urban science. O’Brien’s Perspective advocates for a pointillistic approach that is capable of flexibly integrating and navigating multiple scales within urban science. The author then applies it to public safety and environmental justice, and highlights its utility in shaping equitable policymaking. Also referencing scale, Creutzig and coauthors argue in their Perspective for bridging local interventions with global climate goals, and propose systematic urban climate strategies that empower planners to implement effective and inclusive solutions.

Art has long evolved in tandem with technological advancements; innovations such as new pigments, drawing tools and image-capture mechanisms catalyze fresh aesthetics and revolutionary artistic practices. This evolution mirrors urban studies, in which technological advancements drive innovation and new methodologies. The Article by Galleguillos-Torres and Grêt-Regamey uses cognitive psychology experiments that incorporate state-of-the-art immersive 360°-stimuli simulations of neighborhood scenes to investigate people’s preferences for neighborhoods in two Western European cities. They found that despite urbanization pushing populations towards the outskirts of growing cities, residents tend to favor either rural or urban environments over periurban neighborhoods. Looking ahead, echoing the dynamic debates surrounding artificial intelligence-generated art, the Comment by Cuppini and coauthors investigates possible pathways for opening a research field that is capable of tackling the critical tensions redefining contemporary urbanity in the era of digitalization.

Art echoes deeply within urban spaces, and threads together culture, identity and innovation to shape the cities of today and tomorrow. Elements such as line, color, scale and technology transcend mere ornamentation; they critique, challenge and reimagine urban landscapes to uncover hidden inequities, inspire actionable solutions and unlock transformative opportunities. Let these echoes of art inspire us to envision and create urban spaces defined by creativity, empathy and resolve.