I really don’t care for the Millennium Giants story arc. So I fully admit that I give the Kesel, Val Semekis, Rodier and Koblish story from Adventures of Superman 557 (May 1998) short shrift.
Superman Blue in incapable of stopping or even affecting the Giant shredding its way through Mexico City. He calls on the Justice League, and Green Lantern, Martian Manhunter, Flash, Aquaman and Steel show up, as well as Superboy. Two other Giants are causing problems, so they split up to fight them.
One is in Markovia. Geo-Force and Terra are facing it alone until Superman Red arrives with some of the Leaguers, as well as the Teen Titans. The Giant does massive damage to the country.
Superman Blue has better luck in Atlantis, with the other Leaguers, and Lori Lemaris.
The story continues in the next issue of Action.