A dimensional fold created by the Goddess, Gaea, to seal her immortal enemy, Boreas. More information on how this place came to be can be found in locating and reading [Titan of the Unforgiving Tundra], being sold by the curio vendor in Snowfall.
This area is a Lord Challenge area, intended to be done with no less than four people for the first half of the area. The items of noteworthy interest are only obtained through completion of the boss event near the very end. Ten different items, with six of them being created for particular class types in mind, have been created for the trials that await the end. Best of luck, and learn to work together to reach the end.