The movies? They're obviously talking about Barad-dur and Orthanc.Dont think so. Isnt it about the Saruman's and Sauron's towers? (in other words how Saruman betrayed everyone else by allying with Sauron)
The books? Tolkien wrote in a letter that they're Orthanc and Minas Morgul. Though he wrote in another letter that it can also be any combination of the towers.
As Yaroslavl, vassalize Saruhan! (and maybe also conquer Gonder)New achievement form alliance with Saruhan? Stop Aragon?