Families and friends of those killed in the bombing place flowers, wreaths and other mementos on their loved ones Chairs in the Field of Empty Chairs after the Remembrance Ceremony. The items are left on the Chairs for 72 hours. As part of the preservation process, staff photograph each Chair. Then, as each memento is removed, it is tagged with the name of the Chair and the date removed. Inside the Archives, the artifacts are assigned a number and entered into the artifact database. They are carefully boxed and stored in collections storage for generations to come.