Iron Man, Vol. 3 #48 (2002)

The Frankenstein Syndrome, Part 3
Tony faces off against Ultron, only to learn the true reason for his return and for his armour's sentience. He saves many of the Sons of Yinsen, but when the battle with Ultron leaves their floating city rigged to self destruct, he's found himself faced with the impossible task of mass evacuation.
Release Date: 2002