We often say that climate change threatens cities. But if we are being more honest, what is truly being shaken today is not the city itself, but the way humans have lived. We are living longer than ever, holding more powerful technologies than ever before, and yet being pushed into the future without having built the social, spatial, and ethical structures capable of absorbing that speed. Climate change, the advent of a longevity society, and technological transition are not separate problems. They amplify one another and converge into a single question: How can humans continue, all the way to the end?

Sim Eternal City begins with this question. It is not a proposal for building just another city. It is a storytelling framework that uses the city as a medium to redesign human sustainability. We are not satisfied with imagining a safer shelter or adding a more efficient system. Instead, we ask: in an era when cities themselves can disappear, what kind of structure can hold together the full span of human life—life, work, care, memory, and death—without breaking apart?

The ten points introduced here are neither a feature list nor a technology roadmap. They are coordinates for thinking—ways to take one question apart and reassemble it from different angles. Why define the first citizens as elderly people displaced by climate collapse? Why call humanoid robots “citizens”? Why does this city speak of coexistence rather than escape? Why design a city around an 18-minute rhythm? All of these questions ultimately lead to one deeper inquiry: To what extent can a city take responsibility for the final chapter of human life?

The best way to read this text, therefore, is not to treat Sim Eternal City as a finished answer, but as a framework of questions you can apply to your own city and your own life. These ten points are not a conclusion; they are a beginning. In the age of climate crisis, longevity, and technological transition, they form a map for asking—together—what shape human continuity should take in the cities we inhabit today and the cities we have yet to build.

1. Sim Eternal City is a future city storytelling framework that asks how humans can continue to the very end in an era where the existential crisis triggered by climate change overlaps with the rise of a longevity society and technological transition.

2. The first citizens envisioned by this city are elderly people who have lost their homes due to climate-driven urban collapse. The second citizens, who will build coexistence with them, are defined as humanoid robots—recognized here as “citizens.” On the premise of coexistence between these two, the city redefines and designs invisible assets such as connection, memory, and preservation as core urban infrastructure.

3. Sim Eternal City is neither a dystopian escape plan nor a substitute city, and it is not a second Noah’s Ark. Rather, it is a parallel urban layer that expands the functional spectrum of the city through the coexistence of the Land City and the Floating City—and a new mode of urban operation that complements existing cities.

4. This framework designs the rhythm of life as an 18-minute city (15 + 3). In the Floating City, 15 minutes completes essential living infrastructure (essential needs), while the additional 3 minutes are dedicated to recording, memory, education, and transmission—an operational unit that connects past, present, and future within a single city.

5. The overarching socio-economic architecture of the Sim Eternal City. It replaces the traditional one-way path of aging by allowing citizens to fluidly and bidirectionally transition between a high-paced capitalist lifestyle (Land City) and a purpose-driven, communal care lifestyle (Floating City).

The overarching socio-economic architecture of the Sim Eternal City. Silver Communialism is not removed; rather, it is positioned as a sub-economy that citizens can actively choose. This model replaces a rigid, one-way aging process by allowing individuals to fluidly and bidirectionally transition between the Land City's Capitalism and the Floating City's Silver Communialism based on their personal desires and life stage.

6. The Life Tree Nexus is the digital brain of the city where physical remembrance transitions into eternal digital continuity. Integrated into the "18-Minute City" rhythm, it occupies a vital 3-minute daily window dedicated to memory, recording, and cultural transmission. More than an archive, the Nexus serves as a business model that empowers silver citizens to work as curators and guides. By transforming personal histories into an "open museum" and a platform for memorial tourism, the Nexus turns human legacy into a vibrant, revenue-generating civic resource.

7. No Stone Tombstone is the death-care pillar of the Sim Eternal City, designed to solve the urban land crisis caused by traditional cemeteries. By replacing static, space-consuming graves with a distributed ecosystem of floating memorial islands, urban Dolmen Kiosks, and mobile ceremony vehicles, it shifts the focus from physical occupation to temporal continuity. This adaptive infrastructure prevents the infinite expansion of graveyards, eventually allowing cities to reclaim legacy cemetery land for public housing and turning death care into a sustainable, space-efficient urban service.

8. The operation of the city is completed through a compact structure and mobility-centered execution. Movement, delivery, healthcare, and death care are connected through various forms of mobility, and mobility is redefined not as a mere means of transportation but as Purpose-Built Vehicles (PBVs) that carry urban functions.

9. This framework begins its development and validation with the New York scenario, aims to operate a Floating City prototype by 2040, and designs a long-term evolution toward integration at the level of a “Floating Borough” by 2080.

10. At the same time, the framework is intended to spread and be applied so that other coastal cities around the world can create their own hopeful urban narratives in their own languages—and eventually implement Floating City prototypes in reality.

Updated February 22, 2026: We have refined the Sim Eternal City framework to better reflect our evolving vision. This update introduces two key terminology changes and one new core concept to ensure our language stays aligned with the project's long-term goals. For a full breakdown of these changes and why they matter, read the detailed update here.