The most valuable monument of Szadek is the parish church of the Assumption of the Blessed Virgin Mary and St. James the Apostle, built in the years 1333–1335 in the Gothic style in place of the wooden one destroyed by the Teutonic Knights in 1331. The temple was expanded before the middle of the 14th and mid. Sixteenth century, also after 1868 and in 1905. It is a three-nave, hall structure, supported by buttresses. In the facade and in the passage to the sacristy it has profiled pointed portals. The naves' vaults from the 16th century: stellar in the presbytery and in the main nave, net in the side ones. Exterior doors to the sacristy made of hand-forged sheet metal from the 15th century. Fragmentary polychrome by Jan of Wrocław from 1451. A set of 5 renaissance altars from the beginning of the 17th century. Music choir from the 16th century supported on porters decorated with carved chains. Late Renaissance pulpit from the first half of the 17th century. Bronze baptismal font, Gothic with a crucifixion scene from the 14th century. Gothic Pietà from the mid-15th century. A number of valuable tombstones and epitaphs, the oldest from the 16th and 17th centuries. Next to the church, there is a belfry, which is a defensive tower with narrow loopholes. On the walls you can see traces in the form of round depressions after not using a fire drill, and stone cannonballs embedded in a memorial.