Icecrown obelisk

From WoWWiki

This article or section contains lore taken from Warcraft III: Reign of Chaos, Warcraft III: The Frozen Throne, the manuals, and official bonus maps.

There were four Icecrown obelisks surrounding the pinnacle of Icecrown — which contained the Lich King trapped in the Frozen Throne. Arthas defeated Kael'thas, Lady Vashj, and the demonic Illidan to activate the four Icecrown obelisks to enter the Icecrown glacier door.