Here’s a piece from ye Olde days of ye Webbe…
…which catalogues mega-structures – what I’ve dubbed Ultra-Sized Constructions. One of my comment writers, sweetcement, noted an idea of a ring around the Sun that wasn’t a ribbon like Ring-World. A hollow, rotating habitat is another option…
Topopolis: A long, cylindrical object, rotating for gravity, and wrapped
around a star in a spaghetti-like mass (or mess). The concept was invented
by Pat Gunkel and mentioned by Larry Niven in “Bigger than Worlds”, but as
far as I know nobody has yet had the audacity to write a story about it
(unless you count Greg Bear’s _Eon_ and _Eternity_, which describe a
vaguely related concept).
Imagine walking around such a gargantuan construct – 1 billion kilometres around. At 40 km a day it’s a journey of almost 70,000 years, and it takes our Earth 1 year at 108,000 km/h.