The Seventh Gate of Gondolin, named the Great, was the Gate of Steel that Maeglin wrought after the return from the Nirnaeth Arnoediad. It lay across the wide entrance to the Orfalch Echor. There was no wall, but on either side were two high, round towers, many-windowed, and tapering in seven storeys to a turret of bright steel. Between the towers stood a mighty fence of steel that could not rust, ending in a bitter spike, and between the pillars were seven cross-bars of steel. In each space were seven times seven rods of upright steel, with heads like the blades of spears. Above the midmost pillar was raised a mighty image of the king-helm of Turgon, set with diamonds.

The Gate was opened by striking on a bar, which made the fence ring like a harp, giving forth clear notes that ran from tower to tower. Then riders would issue from the towers, and from the north tower one rider came forth on a white horse – the Warden of the Great Gate.