Arcologies

Comparing size of a TL-12 arcology to modern Earth buildings.

The arcologies on Willow typically support 100,000- 200,000 residents each

Arcologies typically have public-access areas on the lower floors--commercial districts/malls, parks, stadiums, convention centers, and so on.  The ones near water will also have docks.  Upper floors will usually be residential, with several floors sharing large, open park areas fed by mirrors that bring in and concentrate sunlight.

Underground maintenance includes waste processing, dedicated fusion plants, geothermal taps, an so on.  Subway stations are also located underground.

The skin of the arcology is covered over with polarizing windows that double as solar cells for supplemental power and to help regulate internal temperature.