A region of space that cuts off subspace communication, where the Scimitar ambushed the Enterprise-E.
The Bassen Rift is a region of space that prevents subspace communication. It lies on the route between Romulan territory and the Federation.
In Star Trek: Nemesis, the Enterprise-E races toward a Starfleet fleet but is ambushed by Shinzon's flagship, the Scimitar, inside the rift. Despite help from two Romulan warbirds under Commander Donatra, the Enterprise is badly damaged. Data sacrifices himself to destroy the Scimitar and its thalaron weapon.