Yes, a minaret. While the Turkish rule here was short, they left some traces. This is part of the Cathedral of Saints Peter and Paul. The Turks converted the Catholic cathedral to a mosque and added a minaret. When Poles won back the town, the Turks managed to get into the peace treaty that the minaret must not be destroyed. So the Poles had to keep it, but they put Virgin Mary on top. This is a Catholic church, and signs etc clearly indicated that it targets a Polish-speaking assembly.