The Mountains of the Moon
The grey peaks that make the Vale a fortress and its hill tribes a menace ÔÇö Stone Crows, Burned Men and Black Ears who bow to no lord and rob every traveler the Bloody Gate doesn't save.
The fuller tale
The Mountains of the Moon are the wall around the Vale ÔÇö grey peaks that make Jon ArrynÔÇÖs country a fortress with one door and give the high road from the riverlands its reputation as the most dangerous stretch of civilized Westeros. Civilized being the courtesy: the mountains belong to the clans ÔÇö Stone Crows, Burned Men, Black Ears, Moon Brothers ÔÇö descendants of the First Men the Andals drove uphill, who have spent six thousand years declining to acknowledge the arrangement and taxing the road in blood and boots.
The storyÔÇÖs best mountain chapter is TyrionÔÇÖs: captured on the high road, freed at the Eyrie, and promptly recruiting the clans on the way down ÔÇö trading Lannister steel for Stone Crow swords and telling Shagga son of Dolf which parts to cut off. It is the tale in miniature: the despised outsider finding common cause with the people the realm pretends are scenery. The clans fight at the Green Fork for the ImpÔÇÖs promise, and the mountains resume their long war with the ValeÔÇÖs knights ÔÇö a conflict older than the kingdom and, on current form, likelier to outlast it.
The fallen of this place ÔÇö if any, they are named here. Spoilers.
No death the chronicle records has come to this ground ÔÇö or none the maesters have set down.