This is where we get all are high tech weaponry.It held all the powerful weapons that the seven have know.It is mostly made from Hephaestus's forge.A minor amount was also made from Daedalus's work shop before he went on his secluded island and turned evil.They are held in metal pods that only the gods of Olympus mad the seven have access too.You may also have assess to are huge arsenal if you join Olympus high.Like the school doors of the janitor closet,you need the pendent with the beginning letter of you name on the back of it to open both the arsenal and Olympus high.But it only works for your blood/DNA,so not just any body with the pendant can open it.
