Significant parts of the fortification/defensive walls of Piran remain well-preserved thanks to extensive, and continued, renovation. The third and largest one sits prominently above and on the East Side of Piran, on Morgoron Hill. That wall has six towers and so high above town, it offers amazing views. Piran’s Town Walls were built in various stages from the 7th to early 16th century. Sections of the old town wall and seven gates still stand throughout Piran today - it's kind of nice to find them all, each with its own feel/design. It cost 3 Euros (at the time of this writing, free for 12 and under, no dogs allowed) to walk to the top of the wall (free to see it from below). Very narrow, and at times uneven stairs as well as low ceilings make it inaccessible for people with mobility issues. I particularly liked seeing the whole town of Piran below, getting a better feel for its layout with the drastic blue of the Adriatic Sea beyond. Beautiful.

The town walls is worth the walk up the hilly narrow streets of Piran. Once you reach the walls you pay to enter but well worth the few euros. You get to climb narrow and low hanging ceiling stairs in the towers and along the walls. The view is amazing

This is quite a climb but well worth it. The entrance fee is very reasonable and the views are spectacular. Be aware that the walls themselves are not all that accessible for people with mobility issues, though most (not all) steps have hand rails. However, you can still get quite decent views from the area immediately beneath the walls.