Crystal Vice

The Crystal Vice is a great rend in the ice and snow that blankets Dragonblight and borders Crystalsong Forest to the north. It shows how thick this glacier is; it's like a canyon, with the skeletons of dragons sticking out of the walls. As it's less treacherous terrain than the surface of the glacier, a road runs through it, but to travel to Crystalsong Forest, travelers must brave the wrath of ice giants and enormous jormungar worms.

There, Ko'char the Unbreakable leads the giants here, and gives quests to fight the invading jormungar worms. Goblins of Nozzlerust Post can be found here as well.

It's here, the entry point from the Caverns of Time is situated and where adventurers meet up with Thrall to help escort him to the Aspects. The group, however, is quickly discovered and groups of ice elementals led by the fearsome ascendant Arcurion will try to stop the shaman from reaching the Wyrmrest Temple, the last bastion of Azeroth's defenders, which is now assaulted by Deathwing's loyal minions in order to finally bring the Hour of Twilight.

It's unknown what has become of the frost giants that once lived here.