Crassus's wall.
Crassus' wall was a wall built by Crassus' soldiers to block the rebels as they attempted to escape through the snowy mountains in Mors Indecepta.
For weeks after Crassus reclaimed Sinuessa, hundreds of rebels had searched for a way past the wall, only to meet a grizzly end.
Following the Rebels escape, Crassus has the wall destroyed using his ballistae and catapults.