Ultima Tower
Eugene Tssui imagined a two-mile-high artificial mountain that would house a million people and draw water from the Bay through its own ecosystem.
Quick facts
- Existence state
- Never Born
- Peak stage
- documented concept
- Research confidence
- high
- Last verified
What it was
A visionary arcology designed by architect Eugene Tssui for the San Francisco Bay Area.
A tapered, biologically inspired tower would combine homes, transport, agriculture, water systems and public landscapes.
Existence timeline
Tssui develops a city-sized ecological structure.
The design reaches roughly two miles high.
Water, transport and agriculture are integrated.
The project circulates through architectural media.
Ultima remains a research vision.
CityLab returns the tower to public attention.
Why it ended
The study never advanced beyond conceptual design and was not commissioned for construction.
Last confirmed trace
Drawings, architect records and tall-building databases preserve the proposal.
What it left behind
Ultima Tower remains a recurring reference point for ecological arcologies at a scale beyond conventional skyscrapers.
How we classified it
The proposed archive unit never reached ordinary public access in the form being documented.
The strongest verified milestone maps to documented_concept under Arrival Score V1.
Sources & verification
Last reviewed 2026-08-01. Sources are linked so readers can inspect the evidence directly.