Image from Steve Bowers
Wyrme, Ouroborous and Spaghetti, topopli in the Cableville system

Long, thin, rotating habitat in orbit around a star or planet, so that the long axis of the habitat passes completely around the orbit at least once. If the short radius of loop is very much smaller than the long radius, then the difference between the inside and the outside radius of the loop is negligible, and the hoop can rotate without noticeable internal distortion.

Also called a 'macaroni world'.
Related Articles
Appears in Topics
Development Notes
Text by Steve Bowers
Initially published on 22 November 2010.

The concept of the Topopolis is attributed to Pat Gunkel in Larry Niven's essay Bigger Than Worlds (1974)