In Kruszwica, there is a mural depicting the legend of the cruel king Popiel. It is the first such work in the city. The story tells of Popiel and his wife's escape from mice that gnawed through the bottom of their boat, preventing them from escaping. The rodents then swam across Lake Gopło, climbed up the castle tower, gnawed through the gates, and devoured the evil ruler and his wife. The legend refers to the famous Mouse Tower, which is located nearby, and the mural captures this dramatic story in a picturesque way.