As time passes, built forms manifest the ephemerality of functions and people. Most forms will outlive the purpose for which they were originally designed, leaving them up to the interpretation of following generations of users. The process of leaving behind a shell severs the relationship between form and function. When a shell persists through multiple cycles of inhabitants, it becomes an artifact—a physical expression of a past era that has transcended time. Our engagement with this artifact is more complex than our experiences of new structures because a new level of interpretation, the collective memory, is involved. The collective memory is not the same as the history of a place. The existence of a particular group of people and function within a form is history; history shifts to memory once this group leaves the form behind. The history of the place progresses as new waves of human presence take over. These people leave their own traces on the form, and over time, these traces become the matter that embodies the collective memory.