What are some prisons throughout mythology?

I can't think of any (that weren't a Hel/Hell) so I was wondering if there was one that's kind of like a foundation of sorts where their main purpose is solitary confinement.

For ex. Jesse Faden's FBC, SCP Foundation

I couldn't think of an example from/in mythology it can be one from any Mythology and I kind of wanted to start a thread here going over that stuff if there was one