Donald mentioned finding Leon. He's training in the waterway hidden in District 2. To get there, use the Red Trinity behind the Hotel in District 2 -- it's by the iron bars on the far end. Inside are ...

First, talk to Cid in District 1. Then, head to the Secret Waterway in District 2, where there's one more Navigation Gummi to acquire. Examine the sun mural on the wall (where the moon used to be) to ...