Restoration of Primorska to the Motherland Day is observed in Slovenia every September 15. This significant memorial day commemorates the historical transition of the Primorska region, also known as the Slovene Littoral, from Italian occupation to Yugoslav control following World War II. The region, which borders Italy, was annexed by Italy in 1920, leading to a prolonged struggle for the Slovene minority under Fascist rule. The day marks the signing of the Paris Peace Treaties in 1947, which resulted in Primorska being returned to Slovenia. Although it is an official public holiday, it is considered a working day. The observance highlights the importance of this region, which is recognized as one of the most economically developed areas in Slovenia.