Portal of Mystery
(Key word: transport)
There are three entrances to the cave complex. Two come in from the South, from the mountainside. The West entrance joins to a secret door from the lean-to belonging to Rog, the crazy Hermit of the Hill.
The complex is guarded by two massive iron golems.
The portal itself is burined far into the complex, behind a well-hidden secret door that is securely locked and thrice-trapped.
No one knows where the portal leads. Occasionally a gold bar or a bag of silver ore will appear on the steps in front of the shimmering doorway. Not a single adventurer who has ventured through the portal has ever returned.