The Ultima Tower is a hypothetical supertall skyscraper, designed by American architect Eugene Tsui in 1991. It has been envisioned to be built in San Francisco, California[1] and could accommodate up to 1 million people. With a total height of 3,218 metres (10,558 ft), the tower would be 2 miles tall, and comprise 500 stories if built. It is one of the tallest buildings/man-made structures ever conceived.[2]

The Ultima tower
Ultima Tower.jpg
This picture shows the height of the Ultima Tower
Former namesThe two-mile high tower
General information
Architectural styleModernist
LocationSan Francisco, California, U.S.
Height3,218 metres (10,558 ft)
Technical details
Floor count500
Floor area1,500,000,000 square feet (140,000,000 m2)
Design and construction
ArchitectEugene Tsui Company


The proposed tower would have a diameter at the base of 1,828.8 metres (6,000 ft), and comprise 1,500,000,000 square feet (140,000,000 m2), which is 140 km2 of interior floor space. Tsui proposed that the tower would be home to 1 million people, and would cost an estimated US$150 billion. The tower would use the atmospheric pressure difference between the bottom and the top of the tower to create electricity throughout the tower.[2] The building is intended to handle problems with overpopulation and to create a "mini-ecosystem" for its inhabitants.[3]


  1. ^ Blogball (25 September 2008). "10 Fascinating Buildings Never Built".
  2. ^ a b "The "Ultima" Tower, Two-mile High Sky City". Tsui Design and Research Inc. Retrieved 2010-04-01.
  3. ^ Blain, Loz (May 4, 2008). "Two-mile high termite nest proposed to counter the population challenge". Gizmag. Retrieved July 17, 2011.

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