Lonely Mountain
Tom Shippey notes that in "The Hobbit", the lonely mountain is a symbol of adventure, and the "true end" of the story is the moment when Bilbo looks back from a high pass and sees "There far away was the Lonely Mountain on the edge of eyesight. On its highest peak snow yet unmelted was gleaming pale. 'So comes snow after fire, and even dragons have their ending!' said Bilbo, and he turned his back on his adventure."