Starforts and old world mysteries

Starforts, star citadels, star cities; are intriguing geometric and sometimes symmetrical constructions ranging in size and scale, that have been revealed all over the world through aerial images and ongoing research over recent years. They vary in presence from well preserved, to partially buried or in degrees of ruin.
Alternative researchers think they might be the structures of an unacknowledged civilisation from the old world. Many seem to be connected by networks of canals and other lines in the terrain. Some suggest similarities with cymatics patterns where sound vibrations create form.
The mainstream references claim them to be defensive fortifications, mostly from the 16th – 18th centuries.
The scale of some of these “starforts” is massive, and it is generally unclear as to how they were built to such scale and geometric precision.
This presentation makes no claims as to having definitive answers; instead the purpose is to share images of these features that seem to occur all over the world, to acknowledge their presence, and to wonder at how they may have been created and what may have been their original purpose. At the very least to admire their artistic and creative design.