Gondolin is the hidden Elven city destroyed in J.R.R. Tolkien’s The Silmarillion. It was founded by Turgon in a concealed valley surrounded by mountains in Beleriand during the First Age.
Gondolin’s location was protected from Morgoth, the primary enemy of the Elves in the First Age. The city’s people lived in secrecy for centuries, but its safety ultimately failed after Maeglin betrayed its location. Morgoth’s forces attacked Gondolin, and the city was destroyed in a catastrophic battle.
The fall of Gondolin is one of the major tragedies of Tolkien’s mythology. Survivors included Tuor, Idril, and their son Eärendil, whose later actions became important to the history of Middle-earth. The story also connects the First Age legends with later events described in The Lord of the Rings.
Gondolin is distinct from Doriath, another First Age Elven kingdom, and from Rivendell and Lothlórien, which belong to later ages and appear in The Lord of the Rings.