The Rammas Echor was the great out-wall that encircled the Pelennor, the townlands of Minas Tirith, running for many miles about the fields and farms to guard them from raid and assault. Hastily repaired as war drew near, it could not hold against the might of Mordor: the host of the Enemy breached it and poured across the Pelennor to the siege of the City, and over its broken line the Rohirrim charged at dawn to the rescue.