The Rending of Palaghast
Massive Columns rest at the edges of broken landmasses. Four sets, standing 50 ft tall with 20 yards between each column. The last set floats out past the edge, touching the Abyssal Sea. One must pay a fare to the Bridge Keepers who then unlock the power of the columns. Walking between them and out past the edge transports the travelers to a pocket dimension of the Astral Plane. While the true distance between Domains is thousands of miles or more through the Abyssal Sea, these bridges cut the travel time to mere hours.
Traders and merchants are often seen traveling the Astral Bridges.
Unfortunately, one bridge cannot lead to any Domain. Each Domain only has a select few connections. Many divine scholars and dwarven craftsman have worked tirelessly through the ages to come up with new bridges to circumvent this weakness, but have yet to find a solution.