Saint Adalbert's Stone is the second largest glacial erratic in Greater Poland, located in Budziejewko, approximately 3 km south of Mieścisko, near the Church of Saint Adalbert. The boulder, composed of red granite, has a circumference of 20.5 m, a length of 7.5 m, a width of 4.7 m, and a height of 1.3 m, with 2.7 m of it buried underground. It was formed as a result of the movement of the Scandinavian ice sheet. In 1840, the stone was placed under protection at the initiative of local peasants, and after 1945, it was entered into the register of natural monuments as the oldest object in Greater Poland protected as an inanimate natural monument. The land on which it stands was initially privately owned; after being purchased by the municipality, a road and parking lot were built to provide access.
Legends associated with the stone say that Saint Adalbert preached Christianity from this site and that a nearby spring once had miraculous healing powers, which it lost due to a farmer’s intervention. Another legend claims that the boulder was transported by Saint Adalbert on a golden sleigh, causing the ground to collapse and bury the sleigh beneath the stone. Saint Adalbert's Stone not only serves as a natural monument but is also an important element of local culture and history. Its surroundings and the legends connected to it attract the attention of tourists and researchers alike.