Okay, so a long long time ago, thousands and thousands of years ago, there were people who lived in a place called Lake Mungo. They were very different from us today, they didn't have all the cool toys and gadgets we have. They didn't have TVs, cars or computers, but they still managed to survive and live their lives.
Now, as time passed by, these people who lived in Lake Mungo died and their bodies were buried in the sand. But something interesting happened to their bones. Do you know what happens to ice-cream when it's left out in the sun for too long? It melts, right? Well, the same thing happened to these people's bones, except it happened over a really, really, REALLY long time.
The sun and wind made the bones change over time and some parts of the bones disappeared. But, the bones that were left behind were really important for scientists to learn more about the people who lived in Lake Mungo. The bones taught us a lot about how they lived their lives, the food they ate, and the things they did during their time.
So, that's what the Lake Mungo remains are! A special discovery of people who lived a long time ago and left behind some really important bones that taught us a lot about them.