Standing on the island of Ostrów Tumski northeast of the city center, the Archcathedral Basilica of St. Peter and St. Paul in Poznań is one of the oldest churches in Poland and the oldest Polish cathedral, dating from the 10th century, also the main political centers in the early Polish state. The cathedral's edifice was built in 968 in the fortified settlement of Poznań, now referred to as Ostrów Tumski.

Due to numerous fires, the church was rebuilt and remodeled numerous times. A blaze in 1622 led to its Baroque finish, while in 1722 a second fire changed the appearance of the building to neo-Classicism. Finally, during the liberation battle in 1945 more than half of the cathedral was ruined once again exposing its original Gothic elements which visitors can see today.

Inside, the Poznan Cathedral houses twelve different chapels, including the Chapel of the Holy Sacrament and the Baroque altar with a miraculous crucifix from the former Wrocławska town gate. The Golden Chapel holds the sarcophagi of Polands first monarchs - kings Mieszko I and Bolesław Chrobry. Travel down to the Cathedral’s crypt to see the remains of the pre-Romanesque and Romanesque versions of the Cathedral and a 10th-century baptismal font.