Secon part of my Riggerholm setting. While the first map shows a civilization in its beginnings, the second shows a civilization in its last stage. Some hundred thousand years have passed. Ages are gone when worlds were formed after the wishes of men/sentients, solar systems designed and unbelievable heights of science and culture reached. The home world of men, where the island is situated, while still honored as birth place of civilization, has long lost any political or cultural importance. And so the society slowly began to degenerate - at least the organic parts of it. The island had been covered my kilometer high and wide megastructures, deep into the crust built sky towers and cloud scrapping monuments, while the land itself had been shaped. When 'back to the nature' became fashionable, these structures nearly vanished to make place for detailed planned nature. This changes happened several times.
Now most of the island is green again. Several megastructures still exist, but many of them have lost their functionality. Not because of technological breakdown, but because competing AIs are locked in never ending arguments and discussions how to do things best, or because the AI simply transferred out because they no longer saw the need to serve the needs of organics, or simply because the inhabitants no longer understand how to use the magic-like technology. It's the first time in hundred thousand years that sentients begin to build old-styled cities again.