Mount Doom

Mount Doom is a fiery mountain that was located in Mordor.
== Before the Series ==
Mount Doom was where the One Ring was forged by Sauron. Later, Elrond took Isildur to the Mountain and ordered for the young king to throw the Ring into the Fire. However, Isildur was corrupted by the Ring and refused. 
== The Fellowship of the Ring ==
Elrond mentions the mountain when deciding what to do with the One Ring and that this location is where the Ring will be destroyed. 
== The Return of the King ==
Frodo and Sam finally made it to Mount Doom at the last leg of their journey. After the Ring is destroyed, the mountain later collapses, as does all of Mordor.