True, though magical locations are usually something discussed with a DM and worked into a background, rather than bandied about purely for CO.
As an aside, I once had a discussion where we were trying to figure out how an Otyugh could offer sufficient horror to frighten a high level character to earn the iron will feat. At some point the conversation devolved into a few drifting words: "hole... otyugh... hole... " and we all shared an involuntary shudder and agreed that if a character could go through that, they deserved the feat.