Brimstone Springs is a small settlement high in the Mindspin Mountains of Nidal known for its hot springs: the Soulsheen Baths. Hundreds of people from all over the region come every year to soak in its sulfur-rich mineral waters that fall in natural cascades, giving the town a rather unpleasant smell. These waters then collect to form the source of the Sulfur River, which flows westward out of the mountains toward Usk Lake. Brimstone Springs has also gained a certain amount of notoriety from the golden dream, a special, day-long immersion in poisonous waters that, if it doesn't kill the user, gives him or her visions of the afterlife while permanently dying the skin a deep yellow.1
For additional as-yet unincorporated sources about this subject, see the Meta page.