Okay, so imagine a big box where people in Afghanistan put important papers for safekeeping. These papers could be things like religious texts, letters, legal documents, or even shopping lists! This big box is called a "geniza".
Now, sometimes the people who put these papers in the geniza forget to come back and get them. So over time, the box fills up with more and more papers until it's overflowing!
But what's so interesting about this geniza in Afghanistan is that it's hundreds of years old! That means people have been putting papers in it for a really long time. And because Afghanistan has had many different rulers and cultures throughout history, there are all kinds of different papers in the geniza from different times and places.
People who study history and culture like to look at these papers to learn more about the past. It's like opening a treasure chest full of secrets!