The church in Siesby stands on the banks of the Schlei. Surrounded by the village of Siesby with its old, reed-roof houses, the church bears witness to a long history dating back to the 12th century. At that time, the building was presumably a chapel made of field stones that served the settlers and fishermen as a place of worship or as a refuge. The church that stands today is built partially with bricks and partially with split granite. Little by little, it gained its present form through various additions, and its style is reminiscent of the churches of Denmark with their massive towers and saddle roofs. The last renovation of the church took place in 2015. The roof interior was restored and the exterior of the roof completely redone, the cracks in the sanctuary were also repaired and the paintings cleaned and restored. In 2017, the church of Sieseby will open its doors to the Schleswig-Holstein Music Festival for the first time.