Dry Wastes Gem Mine

The Dry Wastes Gem Mine was originally a naturally-occuring series of caverns found by explorers nearly 500 years ago. It didn't take long before many gems, the result of ancient volcanic activity, were found in the caves, causing a rush of explorers, miners, and businessmen all attempting to take what they believed was easy-found wealth.
The wealth, however, was not as simply taken as most had hoped. Creatures began emerging from the darkness, beings that were unfamiliar to the topside world in both origin and goals. As many flooded into the caves, the numbers returning with their prize were much, much fewer, and rarely came back unscarred. Despite several attempts at mobilizing joint-military ventures into the mines, the unknown threat was simply too much of a challenge to be mitigated.
In the following centuries, a general agreement was reluctantly made by the surrounding city-states that no one entity would be able to own the caverns, as most very quickly found they did not have the manpower or resources to protect their interest both travelling to, and in, the mines. While large-scale excavations were generally not cost-effective, teams of adventurers and monster-hunters still regularly delve into the depths in hopes of finding treasure, adventure, and excitement.