Speak with Adarrah at Thistleshrub Valley in Tanaris.
The pyramid inside of the Maker's Terrace in Uldum can be used as some kind of super weapon that will end all life on Azeroth.
<Belloc thinks a moment.>
You must continue the good research that you've begun. Head south to the desert of Tanaris. There's a caravan there that's about to leave for Uldum.
Perhaps you can tag along.