Search the Antechamber of Uldum for an intact artifact.
I studied these ruins for years trying to find a way in. We even took a good chunk out of the gate, only to find impenetrable walls beneath. Now the cataclysm may've wrecked everything in there something fierce, but it's done what we couldn't and opened a way in!
I'd like you to have the honor, lad. Head on in there and see if anything's been left uncracked. Be careful though... there's no telling what, or who, might be stirring in there.