Bridge of Esgalduin
This article describes a concept which is mentioned in J.R.R. Tolkien's works, but was never given a definite name.
The Bridge of Esgalduin was built by the Dwarves of Belegost in return for knowledge taught to them by Melian and for pearls given to them by King Thingol. The bridge was constructed of stone and was the only means of entering the gates of Menegroth.