Template:Nosources Arcologies are fully-enclosed areas housing large populations of humans on Earth. The environment on Earth has been rendered unsafe by centuries of industrial-ecological abuse.
Each arcology, built in the 21st century mostly on top of pre-existing cities (and enclosing their historical centers), protects humans from the deadly atmospheric conditions outside while providing a complete and self-contained “world” inside. Most earthlings grow, mature, and die on their planet without ever having seen what used to be known as “the sky”.
Earth arcologies
(Note: This list consists only of items mentioned in the sources. It may be very incomplete.)
(Spoiler Warning)
After the resolution of the possession crisis the need for Earth arcologies was no more.