Arcology

Arcology, a portmanteau of "architecture" and "ecology", is a very densely populated and ecologically low-impact megastructure human habitat with an architectural design to support such a massive project.

An arcology is designed to lessen the impact of a large population human habitation on any given ecosystem. It could be self-sustainable, employing all or most of its own available resources for a comfortable life: power, climate control, food production, air and water conservation and purification, sewage treatment, and so on.

The term was coined in 1969 by architect Paolo Soleri, who believed that a completed arcology would provide space for a variety of residential, commercial, and agricultural facilities while minimizing individual human environmental impact. Soleri describes ways of compacting city structures in 3D to combat 2D urban sprawl, to economize on transportation and other energy uses. He designed "Arcosanti" which is an experimental "arcology prototype" under construction in Arizona since 1970. It applies the principles of arcology to create a pedestrian-friendly urban structure.

Buckminster Fuller proposed the Old Man River's City project, a domed city with a capacity of 125,000, as a solution to the housing problems in Louis, Illinois.

A very large arcology, such as the proposed Shimizu Mega-City Pyramid, is sometimes referred to as a hyperstructure. The structure would be 12 times higher than the Great Pyramid at Giza, and would house 750,000 people, easily the largest man-made structure on Earth.

The Line is a 170 kilometres long and 200 metres wide linear smart city under construction in Saudi Arabia, designed to have no cars, streets or carbon emissions. It's a $500 billion project, anticipating a population of 9 million. Excavation work had started along the entire length of the project by October 2022.

Due to environmental issues and resource depletion in the future, arcologies could become critical to mankind. The scale of engineering required will be possible with the use of carbon nanotubes that can cope with the massive forces involved. The sheer size and strength of arcologies make them virtually immune to earthquakes, hurricanes, and other disasters. Each of these self-contained structures holds everything it needs for human survival. Automation is ubiquitous in these structures with intelligent robots managing almost all construction and maintenance. Energy is provided by solar panels embedded in their exteriors along with wind turbines surrounding the structures. Highly efficient transport systems are located throughout these structures to move travelers horizontally, vertically, or diagonally, at extremely fast speeds.