Board Thread:General Discussion/@comment-26066818-20151018181718/@comment-61022-20151019182807

It was a mistake, all handbooks past and present refer to Attilan as being moved to the Himalayan Mountains after the Atlantic Ocean.

I wouldn't say it was a mistake per-se but more of an editorial change. Probably Stan and Jack intended to use the Andes, but decided later on that it wasn't remote/exotic/mysterious enough and changed it next time it was brought up.