Part 25: Chronopolis - Chrono Cross Guide - IGN

Once everything is done, go to the Dead Sea Ruins (Home), and interact with one of the three glowing points in the water.

Part 16: S.S. Zelbess - Chrono Cross Guide - IGN

Part 22: The Dragon Gods - Chrono Cross Guide - IGN

Part 05: Nikki's Path - Chrono Cross Guide - IGN

Part 16: S.S. Zelbess - Chrono Cross Guide - IGN

Part 10: S.S. Invincible - Chrono Cross Guide - IGN

Part 17: The Einlanzer - Chrono Cross Guide - IGN

Part 09: Hermit's Hideaway - Chrono Cross Guide - IGN

Chrono Cross [Walkthroughs] - IGN

Part 13: Fort Dragonia - Chrono Cross Guide - IGN