Umbrian Highways

The Umbrian Highways are subterranean network of man-made caverns that utilizes the power of the leylines mapped out by the Red Hoods to drill through the rock, mantle, and core in order to get to the Ring of Ruin. They are a series of waterlogged caverns that are traversible by boat and are powered by energy funneled from the exosphere. The ride through the tunnels seems like a relaxing adventure.

The lighting is made of bioluminescent lichen, the scenery is incredible, but the temperature shifts make it into an extreme tourism contender. It is one of the only ways that S.A.D.R.E.S and Penumbria is connected, and is the only way trade can be conducted on a regular basis, as the Watchers' positions and solar storms have to be in the right place for the Briar Wall to be traversible.

There are private vessels which can be taken to reach S.A.D.R.E.S from Penumbria, which is only traversible through the Temple of Aran, that include temperature control and other amenities. However, it is incredibly expensive. The technology used by the Umbrians to circumvent the intense pressure and heat that comes through the highways is a necessity for other species with the exception of the Umbrians who have adapted to it.

This technology is the only viable way if there is some sort of catastrophic emergency, for either society (Penumbria or SADRES) to evacuate or send supplies to the other side. Antumbria continues to be inhospitable to cross and a deathtrap as the Sosios and Antumbrians run free, and the Briar Wall keeps the average dweller out of the loop.