Crypts closed until Easter 2023.
In the vaults of Poznan Cathedral one can see fragments of the Pre-Romanesque and Romanesque cathedral, as well as relics of tombs—most probably those of the first rulers of Poland Mieszko I and King Bolesław Chrobry, as well as relics of a baptismal bowl dating from the 10th century, in which the first ruler of Poland may have been baptised together with his subjects. The second crypt houses a lapidary exhibition of relics of various slabs and stones excavated during archaeological works carried out during the reconstruction of the cathedral after World War II, 1946-1956. The next crypt contains the mortal remains of the archbishops of Poznan. At the entrance to the vaults, there are boards designed by Prof. Zofia Kurnatowska which provide information about the rich history of the cathedral and Ostrów Tumski.