Issued in 2005 these three stamps have pictures and plans of important fortresses in Croatia.
     The first features the fortress at Ilok on the western slopes of Fruška Gora on the east bank of the Danube. The fortress was begun in 1267, and the present shape dates from the middle of the 15th century.
 

     The middle stamp features the fortress of Motuvun built in the 13th to 15th centuries.

    St. Nichola's Fortress is one of four fortresses surrounding Šibenik. The others are St. Michael's (also known as St. Anne's), St. John's and the Šubićevac fortresses. St. Nichola's Fortress was built between 1535 and 1550 by Gian Girolamo Sanmichele according to a design by the Venetian military architect Michelle Sanmicheli.

     Other sets featuring fortresses were issued by Croatia in 2001, 2002, 2003, and 2004.