This is a guide showing the location of all the Elders of the Dungeons. There are 13 total and they are part of the Lunar Festival Achievement. This was the last achievement I needed to complete "What a Long, Strange Trip It's Been" and I now have my Violet Proto-Drake and 310% flying speed. Hurray!
( I was going to do this last year and had all the footage recorded but then my hard drive died and I lost it all. By the time I replaced the hard drive I was too late to re-record everything.)
The Elders are located in Sunken Temple, Blackrock Depths, Lower Blackrock Spire, Stratholme, Zul'Farrak, Maraudon, Nexus, Azjol-Nerub, Utgarde Keep, Utgarde Pinnacle, Drak'Tharon Keep, Gundrak, and Halls of Stone.