Mountain
Mount Shasta
They supposedly built an underground city called Telos beneath the mountain.
Described as a subterranean haven, Telos is said to be lit by an artificial sun and consists of multiple levels with hydronic gardens, schools, and a pyramid-shaped temple.
Modern believers claim that the Lemurians established an underground city, Telos, beneath Mount Shasta after their continent sank.
Believers often claim that these civilizations' wisdom and technologies can still be accessed through spiritual practices and that remnants of their peoples might still exist in hidden or subterranean realms like Telos beneath Mount Shasta.