Porto Darsena

"Hidden within a subterranean cave complex, Porto Darsena's existence is known to few outside of the Medician military. It serves as a refinery for local hydraulic fracturing operations, where the government has successfully tapped a 110 trillion cubic foot reservoir of natural gas known as the Ponere Shale Shelf."

Porto Darsena is a military port in Just Cause 3.

Description
It's entirely underground and it's one of the largest ports in Medici.

Strangely, there's 3 SAMs in the cave. The base has a set of large inaccessible hangar doors on one wall. In the middle of the port is a large concrete structure that looks like a submarine pen, this structure present at a few other ports. The port has a system of roads throughout the cave, and the roads are connected to the civilian roads on the surface.