Gandhari Khilla is basically a big fort that was built a long time ago by some people called the Kalinga Dynasty. It's like a big, strong castle that was used to protect people and keep them safe from danger.
The fort is in a place called Berhampur in India. It's made of big stones that are put together really well, like a giant puzzle. The walls are really thick, so nobody could just break through them easily.
Inside the fort, there are lots of different rooms and buildings. People used to live there a long time ago, and it was also used as a place for the king and queen to stay when they came to visit.
But now, the fort is just a really cool place for people to visit and learn about history. Visitors can walk around the fort and see all the different things that were used a long time ago, like weapons and tools. It's like a big museum, but instead of looking at pictures and reading words, you get to see everything up close and touch it too!
So, to sum it up, Gandhari Khilla is like a big, strong castle that was built a long time ago to keep people safe. Now it's a place where people can go and learn about history and see really cool things.