Finrod is one of my cousins, you haven't met him. Specifically, he's the eldest son of father's youngest half-brother, Arafinwe, who sits on the Noldoran's throne in Tirion in Valinor the Blessed, for he turned back, rather than continue towards Middle-earth. But Finrod and his siblings had the hunger for new worlds in their blood - Finrod especially! And they kept going, taking Finrod as eldest to be their lord. In Middle-earth, finally, something of the wanderlust he had always shown was finally slaked, and he had great friendship of the various folk that we encountered. Nargothrond was his stronghold, and he built it in the caverns of Narog by the river of that name. The dwarves helped him delve it, and great was the friendship that grew between them - enough that to this day folk know him as Felagund, after the dwarvish Felak-gundu - Master of Caves, a title given to him by his dwarvish friends. It was, by all accounts a very beautiful city, but it was a hidden one, built into the caves.