Ustengrav

It is an underground area where bandits appear to have been living, located directly east of Folgunthur, north-east of Morthal, and south-east of Solitude.

Interactions
When you go there for the first time, Bandits and Necromancers are fighting each other. If you travel through this, you will find a door to Ustengrav Depths. The depths have very low level enemies (mostly Skeletons and some Draugr) and at the base of the depths next to a waterfall you will find an altar that will give you a part of the Become Ethereal shout. To get to the main altar, you have to get through the set of three gates opened briefly by the nearby stones that glow when you come near each of them. To do this, you have to use your Whirlwind Sprint shout to leap forward from the farthest stone, then sprint through the gates.

History
Ustengrav is the burial site of Jurgen Windcaller, the mortal progenitor of the Way of the Voice. When the player first reaches Jurgen's tomb, they find that his horn has been replaced by a note summoning the Dragonborn to one of the last remaining Blades. A Dragon Soul can be gained, if the horn is placed on his tomb after the main quest.

Notable Loot

 * Mystery of Talara, Book II, In a circular room with many urns.
 * Orcish Bow of Flames in the cicular room with many urns. (Not Confirmed on PC, not present on Xbox)
 * Word Wall - Become Ethereal (not sure if its a radiant one or not - found it on XBOX wood elf class)

Trivia

 * The path will be blocked off by a cave in if you visit Ustengrav before the quest requiring you to do so. It appears the Necromancers are using the Bandits to dig it open.
 * Behind the waterfall by the altar there is a chest guarded by a leveled Draugr
 * The rocks surrounding the Thu'um altar contain precious minerals such as gold, silver and corundum. They can be found on a series of ledges attached to the opposite wall.
 * There is also a hidden room behind the small "Skeleton Court Room". To get there you have to jump atop the large pillars above you and use the "Whirlwind Sprint" Shout.
 * There is a hidden cellar chamber, with a chest, down some stairs accessible via a lever chain in a small room with a table covered with gold. The chain is above some candles just opposite the table. The small room is down some stairs to the right just before a long thin room with three crypts on the right and a single bridge crossing above.
 * It is very possible that your follower can die, should you have one, because of the sheer number of floor plates there are that shoot flames when stepped on.
 * There is an Arcane Enchanter in Ustengrav Depths.