Nabta Playa is a really old place in the desert where people used to live a long time ago. It's like a big open space with a lot of rocks that were put there on purpose by those old people. They made those rocks in special shapes like big circles and lines, and they did that by moving the rocks to those shapes. They also made a special place for water to go into the ground so it doesn't go away, and they did that by digging big holes in the sand.
All of those things that the old people made at Nabta Playa helped them know when it was time to plant seeds and grow food. They would look at the rocks and see where the sun was shining, and that told them what time of year it was. They knew that when certain rocks lined up with certain stars, it was time to start planting.
Even though no one lives at Nabta Playa anymore, we still study it and learn from what those old people did. We can see how smart they were and how they used nature to help them survive. It's like a really cool puzzle that we're still figuring out today, and we can use what we learn to help us in the future too.