The Hanging Gardens of Babylon were a special garden built by King Nebuchadnezzar II for his queen in the city of Babylon (modern-day Iraq). The garden was built on an elevated platform with many levels, like a big staircase made out of dirt and stone. Each level was filled with dirt and plants, trees, and flowers.
The reason it was called "hanging" gardens is that the gardens looked like they were hanging from the sky because they were so high up. People believed it was one of the Seven Wonders of the Ancient World because it was so unique and beautiful.
To make sure the plants and trees got enough water, they had a complex irrigation system that used water from the Euphrates River. It was made up of water pumps, channels, and pipes so that the water could reach all the levels of the garden.
Some people believe that the Hanging Gardens might not have actually existed, but others think that they did, and that they were an amazing feat of ancient architecture and engineering, especially considering they were built over 2,500 years ago.