The Alpe-Adria souvenir sheet, issued on April 14, is dedicated to the Alpe-Adria Phila 2011 philatelic exhibition. The souvenir sheet, which was printed in 40.000 copies, and the stamp, which has a face value of HRK 10, were both created by Ante Rasic, a designer from Zagreb. The motif of the sheet is the cargo steamboat "Vis" which sank near the entrance to the Bay of Plomin in 1946 when it ran into a naval mine left over from WW2. The motif of the stamp is the cargo ship "Elhawi Star" which capsized shortly after departing from the Rijeka harbor in 1982. Today, these two ships are among popular diving destinations in Croatia and many diving clubs organize tourist trips to explore such sites.
On April 15 Croatian Post also issued a souvenir sheet commemorating the 50th anniversary of the first exhibition of the "New Tendencies" movement, which was followed by a series of exhibitions held by the Gallery of Modern Art in Zagreb between 1961 and 1973. The exhibitions became a movement which gathered avant-garde artists from the whole of Europe, North and South America. The motif of both the stamp and the sheet is a reproduction of the poster for the fourth exhibition, held in 1968, which had the theme of the use of computers in art. The sheet, printed in 40.000 copies was designed by Orsat Frankovic and Ivana Vucic, both designers from Zagreb. The stamp has a face value of HRK 10. The source materials used for the sheet's design were obtained from the Museum of Modern Art in Zagreb.