The Rammas Echor was a great ancient wall surrounding Minas Tirith and enclosing the Pelennor Fields.
History
Rammas Echor functioned as Minas Tirith's second line of defence, the first being the Anduin. First built after the fall of Minas Ithil, the wall was repaired prior to the War of the Ring by Denethor II, the work being completed only a few days before the Witch-king of Angmar attacked. The Rammas followed an almost elliptical course, being further from Minas Tirith in some places than others. It was furthest from the city at the point where the highway to Osgiliath entered, and was strengthened there by the Causeway Forts. When the Witch-king's forces attacked, however, the Rammas was soon breached in many places, and its defenders, too few to hold such a long fortification, were killed or fled back to the city. After overrunning the Pelennor, the Witch-king's soldiers failed to guard the Rammas against any allies of Gondor that might arrive, and so the Rohirrim were able to enter the Pelennor without significant opposition.
Portrayal in adaptations
The videogame The Lord of the Rings: The Return of the King depicts a gate of a wall in the level, "The Southern Gate".
Etymology
Rammas Echor is Sindarin for 'Great wall'.
