10 Largest Megastructures In Star Trek

At the end of Discovery's fourth season, the crew located the abandoned homeworld of Species 10-C. The star system it orbited was surrounded by massive Dyson Rings.

Strangely, despite being able to rearrange planets worth of materials, 10-C's homeworld was theorised to have been rendered uninhabitable by a series of asteroid impacts, prompting the survivors to abandon their home system and move elsewhere.

The crew later found the new home of Species 10-C, concealed by a humongous hyperfield in the shape of a flattened sphere. 10-C's hyperfield was said to have a radius of 228 million kilometres, making it larger than the Relics Sphere (though the actual livable interior area is a bit harder to calculate). The outer shell functioned as a kind of defense, instantly vaporizing anything that attempted to cross it, unless let in by one of 10-C's transportation orbs. Inside the centre of the hyperfield was a star surrounded by more Dyson Rings and orbited by three gas giant planets.