The home of a stable wormhole.
Barzan II is the homeworld of the Barzan, a people with few natural resources. In the Next Generation episode The Price, a wormhole is found in their territory that appears to be stable, and the Barzan decide to auction access to it in the hope of securing their future.
The Enterprise-D hosts the negotiations, and delegates from the Federation, the Caldonians, the Chrysalians and the Ferengi arrive to bid. The Chrysalians are represented by Devinoni Ral, a negotiator who is secretly part Betazoid and uses his empathic sense to gain an advantage. He begins a romance with Deanna Troi, who later discovers his deception.
Geordi La Forge and Data take a shuttle through the wormhole and find that it reaches the Delta Quadrant, but its far end is unstable and keeps moving. That makes the wormhole nearly worthless. Two Ferengi who go through in a pod are left stranded on the far side, and they are later found by Voyager.