Sunstrider Spire

The Sunstriders, a family of high elven lords, ruled Quel'Thalas from this majestic palace. Sunstrider Spire was once a marvel of organic elven architecture, but now its walls are stained with elven blood and its graceful spires shattered like bones. The Scourge, despite its best efforts, never discovered the legendary Sunstrider treasury. This mythic vault lures adventurers and fortune seekers from across the world. Sunstrider Spire is by no means safe, as hordes of elven ghosts and undead guardians stand vigil over the palace.

The current palace of Silvermoon City is Sunfury Spire.

Speculation
It is unknown if Sunfury Spire replaced Sunstrider Spire, which had been destroyed during the Third War, or if the blood elves have since rebuilt Sunstrider Spire into Sunfury Spire. The Sunfury Spire likely replaced the Sunstrider Spire, or rather was built over it, since most of it was destroyed (based on the wording in Lands of Conflict). It is unclear what parts of Sunstrider Spire were left, how much was reutilized, or if it had to be bulldozed for the new structure to be built. It is unknown if Sunfury Spire was even built over the site of the original palace at all.