Want to see the Genius Loci? Focus on the roofs on Portoroz and Piran.
Brief: Every city has its own Genius Loci, the Spirit of the Place. But what is it? How it looks like?
Idea: Cities of Piran and Portoroz are famous due to Annual International Ad Festival Golden Drum, The Birds Reserve and famous musician Tartini, who played violin. That explains why Drum, Seagull and Violin are revealed while looking through those cities streets.
Solution: The way of revealing the Genius Loci on the posters lies in principle of Magic Eye Stereogram. You just unfocus and then focus your eyes, and that's it.