Durin’s Bridge

Another name for the defensive span also called the Bridge of Khazad-dûm. Within the Second Hall of Moria, the Dwarves had created a narrow and treacherous bridge spanning a bottomless chasm fifty feet across. Encroaching enemies would have to cross this narrow bridge in single file, a perilous task against any defence within the Hall. The Bridge was destroyed on 15 January III 3019 during the encounter between Gandalf and the Balrog known as Durin's Bane.

It should be noted that the Durin of 'Durin's Bridge' was almost certainly not the same Durin of 'Durin's Bane'. Though we're not told for certain when it was created, circumstantial clues suggest that the Bridge dated back to the earliest days of Khazad-dûm, and would thus have been created by Durin the Deathless himself, the founder of the Dwarf-city. 'Durin's Bane', on the other hand, refers to his hapless descendant Durin VI, who was one of the first to be slain by the newly awakened Balrog.