Have you ever thought what would be the best gift you could ever give to your posterity? I've always wondered if I've done enough or if my posterity will ever remember me, or if will they ever thank me for all the things I'm doing now. George Bernard Shaw best described what we can do so that our future generations will remember and thank us for all the things we've done.
"Life is no brief candle to me. It is a sort of splendid torch which I have got a hold of for the moment, and I want to make it burn as brightly as possible before handing it on to future generations."
You might ask: "How?"
Keeping a record of your daily blessings will prove to be helpful to your posterity as they will learn from your past principles that are applicable to their present, or your future. There's nothing more precious than a compilation of great testimonies of God's dealings with His people and how you became a living proof of His divine love and mercy to all his children. Keep a journal and record the most important events in your life like your baptism, priesthood ordination, marriage, temple sealing and many other important events.
Most history we're studying right now and the proof of their existence is made strong by the photographs of people involved, places where it transpired and details entailed in the records of the people who cared to record their history. Take pictures and keep them in a safe place wherein no floods will wash it away.
Keeping your family history or genealogy will not only bless you at present as well as the future generations. So keep a journal and save your history.