Ruin of the Giants

 is single person instance that is part of Quest:Sleeping Giant.

Unlocking the instance is bit complicated. Do quests in Wyvern Watch. After that you unlock quest Quest:One Man Left Behind to find Mysterium Explorer Jabel who was left in Thunder Hold. Return Jabel's book to Wyvern Watch to Jerad. This unlocks the quest. Return to Thunder Hold and climb up left pyramid. Teleporter is on top.

Enter the instance and defeat Prion explorers who are trying to capture the Awakened Giant Giras.

Finishing quest awards superior level 55 boots and is part of Sienna Canyon achievements In a Canyon.