NargothrondNargothrond - The other great Noldor city in Beleriand was Nargothrond.  It was built by Finrod, son of Finarfin.  The idea for the two cities was given to both Turgon and Finrod by Ulmo in a dream.


"Turgon son of Fingofin left Nevrest where he dwelt and sought out Finrod his friend upon the island of Tol Sirion, and they journeyed southward along the river, being weary for awhile of the nothern mountains; and as they journeyed night came upon them beyond the Meres of Twilight beside the waters of Sirion, and they slept upon the banks beneath the summer stars.  But Ulmo coming up the river laid a deep sleep upon them and heavy dreams; and the trouble of the dreams remained after they awoke, but neither said aught to the other for their memory was not clear, and each believed that Ulmo had sent a message to him alone.  But unquiet was upon them ever after, and doubt of what should befall, and they wandered often alone in untrodden lands, seeking far and wide for place of hidden strength; for it seemed to each that he was bidden to prepare for a day of evil, and to establish a retreat, lest Morgoth should burst from Angband and overthrow the armies of the North." ~The Silmarillion, chap. 13 (Of the Return of the Noldor)


But whereas Gondolin was inspired by the Noldor home of Tirion, Nargothrond was inspired by the Sindar city of Menegroth.


"Then Finrod was filled with wonder at the strength and majesty of Menegroth, its treasuries and armouries and its many pillared halls of stone; and it came into his heart that he would build wide halls behind ever-guarded gates in some deep and secret place beneath the hills.  Therefore he opened his heart to Thingol, telling him of his dreams; and Thingol spoke to him of the deep gorge of the River Narog, and the caves under the high Faroth in the steep western shore, and when he departed he gave him guides to lead him to that place of which few yet knew.  Thus Finrod came to the Caverns of Narog, and began to establish there deep halls and armouries after the fashion of the mansions of Menegroth; and that stronghold was called Nargothrond." ~The Silmarillion, chap. 13 (Of the Return of the Noldor)