Bunker 9

Bunker 9 is a hidden bunker that Festus led Leo to. It is an aircraft hanger sized workshop filled with tools and weapons, schematics, a map of the camp, and various machine design plans. It is at least around 200 years old, used in the Demigod Civil War, and on a few occasions since. Leo was able to open the bunker using his fire abilities, so it is not sure how other demigods gained access.

Leo finds his Magical Tool belt inside here. It was revealed that Festus was created in this Bunker. The Argo II (flame boat) blueprints were found here.The Bunker can be only opened and closed by a blast of fire, as shown when Leo and Festus each opened it by setting it on fire, probably as a safety measure against enemies.

Bunker 9 is presumed to be the Hephaestus' Bunker during the war. There are probably at least 11 other bunkers, for the other Olympians, though the bunkers of the Maiden Goddesses may not be used.