Well I think there's not as yet enough evidence to corroborate the stories and may never be... People want to believe in these things and fill in the missing pieces for themsleves.
See a map of the Elburz:
http://concise.britannica.com/ebc/art-54788
There's also an ancient legend in Zoroastrian writings about a "Var" or enclosure that was supposed to be a cave to preserve the seeds of life during an ice age:
O Yima! To this mighty Vara then carry families of all males and females who are on this earth most exalted, most excellent, and most beautiful. To the Vara carry the families of all sorts of cattle on this earth, which are most exalted, most excellent and most beautiful.
"To that place carry the seeds of all trees which are most exalted and sweetest of odour on this earth, carry the seeds of all food most eatable in this world and sweetest of odour. Make these couples unfailing in their love, and everlasting by reproduction; so long as the Aryans stay in the enclosure.
"There should be no person who quarrels, no one who slanders, no impure person. There should be no one with filthiness, no one with deceit nor meanness. There should be none speaking evil words, no one with an embellishment of evil spread over the body (a skin disease), no one here who in general has any characteristic of the evil one.
"Make three levels in the mighty Vara. In the uppermost level, make nine such wide enclosures, in the middle level, make six. In the lowermost level, make three enclosures. In the uppermost wide enclosure let 1000 couples, men and women live. In the middle let 600 couples live, in the lowest enclosure let 300 couples pass their lives.
"High above each of these enclosures, use a golden instrument and make doors and windows. By self-light should the inner parts be illumined..."
Source:
http://tenets.zoroastrianism.com/var33.html
Some of the American Indians believe they emerged from cavern structures under the earth. I think it's very interesting to comntemplate these things but there's not a lot of evidence out there yet to confirm anything.
Baha'u'llah's family lived in the province of Nur which is in the Elburz area:
http://www.itto.org/province/province.asp?prv=mzd
- Art
