Source: UNESCO World Heritage
There are six components - Croatia - Zadar,; Croatia - Fort of St. Nikola; Italy - Palmanova; Italy - Pieschera; Italy - Bergamo; Montenegro - Kotor.
Missing postcard: Croatia Fort of St. Nikola, Šibenik-Knin County. If you can help me, please contact me. Thank you.
Postcard 1 - CROATIA - ZadarChurch of Saint Donat from 9th Century, Zadar, Croatia. Thanks to Antonella of Croatia.
Postcard 2 - ITALY - PalmanovaAerial View of fortress town of Palmanova. Thanks to Christina of Italy.
Postcard 3 - ITALY - PeschieraAerial view of Peschiera, Italy. Thanks to Kerstin of Italy.
Postcard 4 - ITALY - BergamoUpper Town of Bergamo. Thanks to Jean-Pierre of France for mailing from Bergamo in August 2016.
Postcard 5 - MONTENEGRO - KotorKotor is a twenty centuries old and itself a UNESCO World Heritage city. Nice stamps of Crna Gora - Montenegro used. Thanks to Michael of South Africa.