Planina Castle, Planina pri Sevnici
Planina Castle is located above the eponymous town square of Planina pri Sevnici in the municipality of Šentjur near Celje and is today in ruins. The existence of Planina Castle is attested at least after 1190, when the first known highland knight Ortolf was mentioned. The original castle already stood at that time, but we do not come across it in written sources until 1227. Planina Castle with its lordship became the property of the Counts of Celje in 1341, when Ulrich of Sanneck bought it from Henry and Ulrich of Ptuj. After the extinction of the House of Celje in 1456, the castle became provincial. Ana Warmbrechtsammer (1897–1933), a German-speaking writer of Slovene descent who wrote the historical novel "Counts of Celje, today and never again" lived in Planina near the castle ruins.