The Archcathedral Basilica of St. John the Baptist in Warsaw, located in the Old Town, is one of the oldest and most important places of worship in Poland. Originally built as a wooden castle chapel at the turn of the 13th and 14th centuries, it gained the status of a parish church in 1313. Between 1390 and 1406, it was transformed into a brick Gothic structure that witnessed many key events in Polish history, including royal coronations and funerals of prominent figures. The archcathedral exemplifies the evolution of architectural styles—from Gothic, through Baroque, to Neo-Gothic—achieving its current form after post-World War II reconstruction. Inside, it houses numerous works of art, such as the Renaissance tomb of the Masovian dukes and Baroque chapels. The cathedral has hosted important state and religious ceremonies, and its walls remember sermons by renowned clergy. An interesting detail is a fragment of a tank tread from the Warsaw Uprising, embedded in its wall. The cathedral has been visited by popes, including John Paul II and Benedict XVI. Between 2012 and 2015, comprehensive renovation works were carried out, and the cathedral now serves as a cultural venue, hosting the International Organ Music Festival. It stands as a unique example of architectural harmony and complex history that continues to influence contemporary Poland.