Most families have photographs, films, treasures, stories and memories that hold a special place in their hearts, even though they're gathering dust in the attic.
The sad truth is that most of those special family memories will be lost to subsequent generations, who will have no idea of their significance or the stories attached to them - unless you preserve them now.
But what's the best way of doing it?
"Too often we let family memories and moments slip away unrecorded or forgotten," says Jonathan Crane, a BBC TV documentary maker and founder of The Personal Documentary Company.
"We wish we'd talked more to elderly relatives about their lives, we let time fade the memories of special events, and we take endless photographs and videos only to let them gather dust in the attic.
"Sometimes we make a family tree - but names and dates on paper can only tell part of the story, and will only be of limited interest to future generations."
But he says there are lots of ways to bring family trees to life.
Many of us possess old family photographs, often without knowing when and where they were taken and who's in them.
Don't just dump old photos in a shoebox and shove them in the attic - find out as much information as you can about the people in the pictures from the rest of your family and write it on the back of the photo or better still, put them in an album.
"Then, when your grown-up grandchildren find that shoebox or album, they'll have a treasure trove of memories to explore rather than a bunch of dusty, meaningless images," says Crane.
And don't be put off if photos are faded and torn - they can be restored.
Old home movie film reels are often hidden away in boxes and need to be watched with a projector and screen if you still have them, and if the film hasn't deteriorated too much. Such films need to be digitised and copied onto DVD, which Crane says isn't necessarily an expensive process.
As with photographs, try and find out about the who, what and where of the people in the films from living relatives.
"Future grandchildren won't be interested in wading through hours of footage of anonymous people, but if they know it was grandfather Fred going off to the war, they'll be more interested," says Crane.
To make a vibrant and living family tree, you need stories about the people in it. Ask elderly relatives to tell stories about their lives - they can capture a time and lifestyle that's gone forever.
You could get a professional company to record the stories, or simply do it yourself. Smartphones have good quality video cameras and audio recorders, so just sit elderly relatives down and record their memories.
Ask about their earliest memories, their own grandparents and parents, growing up, school, meeting their other halves and what life was like decades ago.
Crane says: "If you're feeling ambitious, you can transcribe their stories, add those restored family photos to the family tree, and hey presto you've got a book about the family that will enchant future generations."
Another key to preserving a family's past is family treasures. Jewellery is an obvious one, but family treasures don't need to have any monetary value.
All kinds of things are precious as mementoes - wedding invitations, train tickets, school play programmes - they all help to flesh out life stories.
If you're filming grandma telling her stories, get her to talk about those treasures, suggests Crane.
"They might trigger special memories that illuminate the everyday object," he says.
"One thing's for sure - her great-grandchildren won't be able to make head or tail of that knick-knack from Spain unless they know the story behind it."
Crane says future generations will want to understand their family's past, and adds: "A family tree is a great way to start preserving your family's story, but if you really want to bring it to life, go beyond just the names and dates.
"Make the best of your photos, films, treasures and above all your living family's memories. They're too important to ignore."