historic event
A noteworthy occurrence in the lifecycle of an object which is not directly associated with its status or functioning.
A historic event in the lifecycle of an object is a milestone, unusual occurrence, or noteworthy event which is not directly associated with its status or usage. These include many human activities whose relationship to the object may be closely dependent or entirely happenstance.
The event is associated with the object without directly marking its development stage or regular function. Human activity can provide that association even when the connection to the place is incidental.
The sealing or opening of a time capsule and an exceptional exterior climb are existing examples of this kind of occurrence. They can happen while the structure's status remains unchanged.