From Croatia we took a short-but-sweet 2 day trip to Kotor, Montenegro since it was only a $20 bus fare.
While there, we climbed the fortifications. It is a daunting 4.5 km directly above the city on vertical cliffs, sketchy steps, and a shaky bridge. It was a bit challenging and took us longer than expected, but well worth it. The benefit of traveling in the off season is that we were the only tourists at the top. We had a view of the entire city to ourselves!