The Forgotten Dwarf Settlement
Following rumors and hints from ancient scrolls, the party discovered the ruins of a dwarven watchtower just beyond the frontier near the town of Hadden. Though the tower itself was reduced to nothing but a few crumbling walls, it’s extensive lower levels are still navigable, if badly damaged by battle and shifting earth. Those lower levels sported a feature unusual in a simple watchtower: a ramp wide enough for a wagon leading to a mechanical lift running through the center of the fort down into the depths.
Exploring the deeper levels reavealed it’s purpose: below the fortress was a large cavern containing an entire dwarven settlement, complete with fungus farms, mines, an underground river and a temple to Moradin. A large gate, smashed in whatever conflict brought the place low, leads out of the cavern, presumably into the twisting caves that make up the Underdark.
Exploration also revealed an infestation or orcs being assisted by a band of derro there under mysterious circumstances. Both have since been completely wiped out.