The past two weekends I ran the Dungeon Crawl Classics adventure Sailors on the Sea of Fate for my home group. In the adventure, the players can find a map stitched into the hem of a discared cloak. This map is left for the GM to define.
So I defined it.
The map is inked on old brown lambskin with notes from unknown explorers and leads to something called "The Library of Uthgarion." Sages and sorcerers might know that Uthgarion was a wizrad of some power in Days of Old. The Black Chapel is a well-known landmark in the nearby city of Ghul-Midyan.