An unusual dungeon located in Mendev is the Jutland Wrecks, the detritus of a massive battle between Issian pirate lords for supremacy over the Lake of Mists and Veils. While the battle itself was inconclusive, a massive storm in the night wrecked nearly every ship on the lake, driving them into Jellicoe Bay northeast of Egede. The tangled flotsam of those ruined fleets remains to this day, now overgrown and almost a living reef choked with the waterlogged corpses of the lost, but also the plunder of a half-dozen pirate lords as well as maps to other caches. Few who venture to the frostrimed Jutland Wrecks return, however, reporting unfriendly fey lurking amid the wrack and ruin—both feral nixies and the hateful ice sprites known as koloiaq.
Sources: Pathfinder Chronicles Campaign Setting