Wikipedia
Germelshausen is a 1860 story by Friedrich Gerstäcker concerning a cursed village that sank into the earth long ago and is permitted to appear for only one day every century. The protagonist is a young artist (Arnold) who happens to traverse the locale at the time for the town's appearance. He encounters, and becomes smitten with, a young woman (Gertrud) from Germelshausen. The romantic tale ends with his leaving the vicinity just in time to avoid being entombed with the village and its denizens, but thereby being sundered from his love forever.
The basic concept is an old German motif that appears in works of Mueller, Heine, Uhland and others. The curse may affect a town, a castle or even a single house, but the narratable content remains largely unchanged.
Germelshausen is noteworthy for the affecting nature of the story, and because it is widely credited as having inspired the musical Brigadoon. But the author of Brigadoon, Alan Jay Lerner, appears to deny this in his memoirs, The Street Where I Live, writing "Nevertheless, to this day chroniclers of the musical theater invariably state Brigadoon was based on a folk tale and give Nathan as their authority."