OMG DIAF

Caer Darrow was a temple built in the middle of the first age by a rogue sect of dwarves who worshipped a great serpent named Yeng.  In the cataclysm that marked the end of the first age and the dawn of the second, Caer Darrow sunk beneath the waters of the newly formed Silvermere, there to be lost for 800 years until its eventual discovery by a prominent seer named Nylith.

 Nylith raised Caer Darrow from the depths and, divesting it of religious profanity, used it as a base of operations for many years.  Upon his demise, Caer Darrow was remade as his tomb and was placed once more under the surface of the lake where, over the course of the next 2200 or so years, it passed entirely out of common knowledge and firmly into the realm of myth.

Now in the third age, Caer Darrow has been rediscovered and stands, again risen, on the shore of the Silvermere.