A Bridging Event is a term applied to the exceedingly rare occasions where a connection is established between Reality and The Liminality. Likened in many respects to a black hole, a Bridging Event allows for materials and data to be transmitted into, and out of, The Liminality.
A Bridging Event can either occur on a minor scale, when a Manipulator first experiences their "Education," or can be willed into existence by extremely powerful Manipulators. The Sedona Cult, Magnasanti, produced an extremely powerful Bridging Event, which sent their physical forms, as well as the physical forms of everything within a half mile radius, into the Liminality.
Fatima produced several Bridging Events, whose energy signatures were initially misconstrued as nuclear testing.
Trans-Dimensional Artifacts are the result of a Bridging Event collapsing. Just as matter from the material universe may get trapped in the Liminality, materials from the Liminality may get caught in ours. Repeated Bridging Events can scar the physical locations where they once took place, with observers occassionally detecting anomalies in gravity, and even reporting visual and auditory hallucinations. Nowhere is this effect more prevalent than in the abandoned portions of the GEHENNA Base.