Predjama Castle is must see visit for castle or old buildings lovers. Inside the castle you can see a lot of things on each of 6 floors. Interesting are some hidden passages and caves behind the castle. On the top floor you can visit also big cave behind the castle. There are also some other special groups to discover caves below the castle. And don't forget also to visit world famous Postojna Cave that is just about 10 kms away from Predjama Castle.
Piran is for sure one of the most beautiful cities in Slovenia. It is old mediterranean town located near Adriatic Sea. In Piran you can see some nice old squares like 1st May Square, Tartini Square and Brotherhood Square. All of them are surrounded with nice old buildings. It is nice to sit down at some restourant on Preseren Quay and breath fresh sea air. St. George Church is located on small hill above the city so it would be hard to miss it. From there is nice view in Strunjan direction. I suggest you also to climb on town walls where is good view on the city and around.