You can go to your bookshelves in the Library and admire them, and reminisce about your world travels. And you can tap on them to revisit the location where you got the memento, and read interesting facts about it.
HISTORICAL NOTE: The very first memento was carried by a Neanderthal named Glugg, who brought a particularly nice stone club back with him after visiting a neighboring cave.
HYSTERICAL NOTE: All Historical Notes are vetted for accuracy by our research partners at Glibbitz, Glibbitz, Glibbitz & Noid.