Ring of Doom

Ring of Doom is an area located in the Undying Lands. It lies south of http://lotr.wikia.com/wiki/Two_Trees_of_Valinor  and west of Valimar.

Location
It is said very little/nothing about this area in the books of Tolkien. As seen on the map, Ring of Doom is an area and not a fortress/city of any kind. It lies south of Two Trees of Valinor, west of Valimar and northeast of Valinor.

Etymologi
Why the place is called Ring of Doom is unknown. And it's rather weird that it is called so, because the Undying Lands are a peaceful land.