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 Frozen Throne Gate.
Four stone obelisks carved with runes of powerful magic surround the Frozen Throne. Bridges of pale blue, translucent energy stretch from the obelisk platforms to the Frozen Throne. Jets of frost periodically spew blue flames into the air, and there are glyphs carved into the rocky ground surrounding the Frozen Throne. Whoever wishes to enter the Throne Chamber, to risk the Lich King’s wrath, must activate all four obelisks.