Eloyah

The island city of Eloyah is the last artefact of the Adar civilization. Nobody knows why it didn't disappear with all the rest of the Adar crystals, but the Psionic Academy of Laric would really like to know and as such spend a lot of time investigating Eloyah. However, they refuse to let anybody else visit, although boat tours can view the structures from the lake in the summer.
Lord Kinekoro of The Rahjs doesn't really care what a bunch of jumped-up Halflings say, though, and happily made his base underneath it, researching the ancient Adar crystals while overseeing the situation in Hengal.
The Party accessed an underground area of the city by traveling for days through the hidden underground tunnel from the village of Hengal, which passed under the lake.