After my grandparents and father died, I inherited a lot of family heirlooms, documents, and "memorabilia". Some of the most amazing ones are the journals written by my ancestors over the centuries. A lot of it covers day to day life during their lifetimes, their thoughts on events that occurred locally/nationally, things that happened to other members of the family, etc.
Since I received them and began to really read them, I decided to start my own, to be passed down as well. If humanity is still here in a century or two, and the "inheritance" survives, one of my relatives/descendants can read them and gain some insight into the times in which I lived.