The Open Archive is a treasure in Pikmin 2, where it is actually a bean tin. It is found on the fourth sublevel of Submerged Castle. Along with two sets of Bulbmin, there is a Careening Dirigibug and Volatile Dweevils, as well as bomb rocks falling from above throughout. This treasure could be anywhere; it is large and, therefore, hard to miss. Remember to be quick so as to avoid a confrontation with the Waterwraith.