Rudkhan castle is a really old building that people used to live in a long, long time ago. It's in a country called Iran, which is far away from where you live. The castle is on top of a tall hill, which means the people who lived there could see things that were far away and keep an eye out for any danger.
The castle has lots of rooms where people would eat, sleep, and do things like work or learn. There were also places where people could store their food and supplies so they would be safe. The walls around the castle were very thick and strong, which helped keep the people inside safe from attackers.
Back when the castle was built, they didn't have big machines like we do now to dig and move things. Instead, lots and lots of people had to work together to build it. They used big rocks and stones to make the walls and towers of the castle, and they had to work really hard and be very careful so that everything was in the right place.
Nowadays, people don't live in Rudkhan castle anymore because it's very old and not very comfortable. However, lots of people visit it to look at the beautiful architecture and learn about what life was like a long time ago. It's like a big piece of history that you can explore and learn from!