Okay, so let's talk about the Imperial Castle in Poznań. It's like a really big and fancy building that was built a long time ago when some countries were ruled by Emperors.
The castle was first built in the 13th century, which was a really, really long time ago. Since then, it has been rebuilt and changed many times over the years.
At one point, the castle was even used as a prison! But now, it's a really cool place to visit and learn about history.
Inside the castle, there are lots of rooms and special places that you can explore. You can see what it looked like when it was first built, and you can learn about the different people who lived there over the years.
It's important to remember that castles are really old, so there are some parts that might be a bit scary or dark. But as long as you have a grown-up with you, you'll be able to explore safely and have lots of fun learning about the history of the castle and the people who lived there.