Millennium Tower is a 170-floor skyscraper that was envisioned by architect Sir Norman Foster in 1989, planned for 2 kilometers offshore in Tokyo Bay.
The design calls for a cone-shaped pyramid 840 meters high, with a base about as big as the Tokyo Olympic Stadium and glass sides for natural lighting. It is intended to be constructed on water, with boat and bridge access. Since the tower was planned for an area with frequent earthquakes and hurricane-strength winds, the shape is aerodynamic to reduce wind stress, and helical bands are wrapped around the tower for structural support. Steel tanks at the top of the tower are filled with water, and can be rotated as a counterweight against wind.
The tower is a self-contained arcology containing one million square meters of commercial development and housing for 60,000 people, split into sections. Offices and light or clean industries are in the lower levels, apartments above, and the top section houses communications systems and wind or solar generators. Restaurants and viewing platforms would be interspersed through all sections.
Horizontal and vertical high-speed metro lines provide long-distance travel, with cars designed to carry 160 people stopping at intermediate five-story 'sky centers' on every thirtieth floor. Each 'sky center' is decorated by gardens and mezzanines, and provides a particular service such as hotels or restaurants. Short-distance travel is by lifts or escalators.
From The High Rise Site:
This building, almost twice the height of Sears, would have a resident population of 50,000. It is estimated that this tower would cost 10billion to build and have an impressive floor area of 1,039,206m squared. The tower was the victim of the bursting of the real-estate bubble in Japan, but Foster maintains that he still hopes to build a version of this building. An unpublished variant of this design, conceived for a Shanghai site with Donald Trump, was called the M Tower. Unlike the Millenium tower with it's central core, the M Tower would have a hollow centre, allowing sunlight to penetrate from one side to the other. Working with the Obayashi Corporation, the clients, they were able to demonstrate that the Tower would be able to be self-sufficient and even process it's own waste.