1991 | San Francisco, California, USA
Ultima Tower / Sky City
“Sky City/Ultima Tower,” the tallest viable structure ever conceived, standing 3.2 kilometers (2 miles) tall and 1.6 kilometers wide at the base.
Cost: estimated - $150 billion
Height: 10,560 feet
Location: San Francisco, California
“The Ultima Tower was a hypothetical supertall skyscraper, conceptualized and designed by American architect Eugene Tssui in 1991. It has been envisioned in San Francisco, California and could accommodate up to one million people”
-Wikipedia
An African termite mound, nearly 6 meters high. The termite mound is possibly the greatest engineering feat in the natural world. The design works in a dense-city context as it contains its own climate control system.
(Left) Relative size comparison to worlds tallest buildings, (Right) Hand drawn renderings