Desperate to find this book, Far-future Earth, floating cities, human sacrifice, forgotten technologies

Question

I read this deeply immersive book, set in far-far future Earth.

Humans had reached immense tech heights, but had lost all their technological knowledge and were regressed to medieval-esque lifestyles. There were ruins of future-tech everywhere, floating cities where the remnants of the overclass still lived, supplied by a handful of shuttles that brought them food from the people living on the ground.

There was an orbiting city where some inhuman being lived and it took human sacrifices up to consume.

There was a system of giant towers (shaped like the Eiffel tower) stretching from Asia to Europe as a cable car transport system.

The main protagonist goes on a journey to rediscover the keys to all the forgotten tech. In the end he finds a forgotten library which uploads all the knowledge of the lost civlisation into his mind.

Any ideas? I'm 90% sure I didn't just dream that I read this.

Answer 1

This is Ilium by Dan Simmons and its sequel Olympos.

The Wikipedia summary doesn't really cover any of the things you mention; the events set on the future Earth are just one of the three separate plotlines. However, the forgotten future tech, an orbiting station with a monster taking sacrifices, and the cable car transport network are a match.

In fact most of the points you mention - eg the revelation that the monster is

Caliban

and the travelling via cable car to the forgotten upload library are from the second book; I wonder if you only read that?