The Cathedral of the Immaculate Conception in Koszalin is a former parish church and at the same time the oldest monument of the city. Inside the building visitors can admire many valuable objects, as the object itself has been enriched for many centuries. Inside is a Gothic crucifix, a thirteenth-century baptismal font, neo-Gothic organ, and a picture of the "Resurrection" by August Friedrich Hauptner.
The church itself was built in the fourteenth century as a three-nave basilic-type temple. Light reaches its interior through windows that adorn colored stained glass. The side walls of the cathedral are supported by twelve pillars, symbolizing the apostles. A powerful fifty-and-twenty-meter tower was built here, where a clock was set in 1754.
Apart from the building itself, it also delights its equipment. The new altar was erected in 2001, but contains elements of its predecessor dating back to the 16th century. There is also an early Gothic baptismal font made of soft shell shells, one of the oldest objects in the cathedral. In addition, the cathedral can admire the 14th-century crucifix located on a rainbow arch.