The Archcathedral Basilica of St. Peter and St. Paul in Poznań is one of the oldest and most important churches in Poland, with a history dating back to 968, when the Diocese of Poznań was established. Located on Ostrów Tumski, the cathedral is the burial place of the first rulers of Poland and is believed to be the site of the baptism of Mieszko I. The current Gothic form of the cathedral, constructed from the 14th century, was partially rebuilt after the destruction of World War II. The interior is rich in artworks, such as a polyptych and stained glass windows, and houses many valuable tombs, including those of Bishop Jordan and cardinals. Since 2017, the cathedral has also served as a stational church during Lent. Architecturally, it features a three-nave basilica with a ring of chapels, and its exterior decorations include flying buttresses. Interestingly, the crypts contain relics of earlier structures and the tombs of the first Polish rulers. The organ, built in the 21st century, completed a long process of modernizing the cathedral’s musical instruments, which began in the 15th century. Combining rich history, cultural significance, and architectural beauty, the cathedral is not only an important monument but also a site of great spiritual and national importance.