Dungeon Crawl Classics - Rise to Glory
From Punjar: The Tarnished Jewel:
The Nether Gates: Believed to be a simple epithet noting Punjar’s odd-score gates and gatehouses, the title carries a greater meaner for those acquainted with the city’s dweomered past. Eldritch gates are concealed about Punjar, mimicking obscure, esoteric sigils. Portals to other places, planes, and times, the gates and their powers are closely guarded secrets, drawing conjurers, fiends, and travelers from throughout the multiverse.