Shinra Mansion (Disc 1) - FF7 Walkthrough
Shinra Mansion is the same mansion at the northern end of Nibelheim that we went through during the Kalm flashbacks. There is quite a bit to do inside of this place but let's start with the treasure chests. There's a total of four items for you to collect here, all of which are listed below.
If you care about the Enemy Skill Materia you should keep an eye out for the Jersey enemies in the mansion. They can teach you the ???? Enemy Skill which deals more damage the lower your HP is, not the most impressive Enemy Skill out there.
Use my screen shot above for some guidance throughout the mansion of where the treasure chests are - ignore the safe for now and head downstairs once you've collected all of the chests. Go down into the same room where Sephiroth lost his mind to find Sephiroth there again, losing his mind.
As he flies out of the room he throws a Destruct Materia at Cloud, pick that up and then exit the room. Wave to Vincent as you run by his room and go back upstairs - this time to the safe. This is technically where Vincent's Side Quest begins and the Shinra Mansion one ends. If you'd like to unlock Vincent, claim the Odin Summon and get Red XIII's Cosmo Memory ultimate Limit Break then follow the link below.