Since the beginning, the Spire has been surrounded by the Astral Sea, a vast ocean of silvery fog and dark space containing portals to every floor of the Spire. It is only here that one begins to get a feeling for the true immensity of the Spire and the hundreds of worlds contained within.
The Spire itself stands at the heart of the Sea, an immense black tower with no bottom or top, and the Sea spreads out from there for endless leagues. Rumor says that if one were to travel all the way to the edge of the Sea one would find the inverted curvature of the Spire walls as though the entire Sea were actually contained within the walls of the Spire, but none can prove they have seen such a thing.
There are four main regions of the Astral Sea: The Shallows, Chaos Currents, Dark Space, and The Wilds.
Navigating through the Astral Sea is extremely difficult due to a lack of directional meaning and ever shifting natural landmarks. Most of the sailors of the Sea refer to the Spire as the Center and orient their directions around that, choosing to keep their ships oriented as though the Spire is ‘down’. Navigation requires skill, magic, and a knowledge of the landmarks scattered around the Sea.