Lika-Senj

Plitvice Lakes National Park's sixteen lakes owe their vivid turquoise and green colours to the same process that built the lakes themselves: dissolved minerals in the water, mainly calcium carbonate, precipitate out and form travertine barriers as the water flows downhill, and these natural dams are what create the lakes' stepped, cascading structure in the first place. The mineral content also scatters light in a way that shifts the water's colour depending on the concentration of algae, minerals and the angle of sunlight, which is why the same lake can look a different shade of blue or green from one visit to the next. The travertine barriers themselves are still actively forming today — the park is, in a real sense, a landscape still under construction rather than a fixed, finished formation.

The park's wooden boardwalks and footbridges thread directly across and alongside the cascades, close enough to feel the spray at several points, connecting the Upper Lakes (Gornja Jezera) and Lower Lakes (Donja Jezera) sections into a single walkable circuit that most visitors cover in four to six hours depending on the chosen route. Electric boats cross the largest lake, Kozjak, connecting the two main entrance areas without requiring a full walk around, and a park shuttle bus links the more distant sections. Arriving at the entrance closest to opening time is worth the effort specifically to get some real distance ahead of the day's tour-bus groups, since the boardwalks are narrow enough that a crowded circuit moves considerably slower than an early one.

The Velebit mountain range, Croatia's longest at over 145 kilometres, runs along the county's western edge, its northern reaches protected within Northern Velebit National Park — a genuinely wild landscape of karst formations, deep sinkholes and rare alpine flora, popular with serious hikers rather than day-trippers given the terrain's remoteness. Where the mountains meet the coast sits Senj, a small historic town whose Nehaj Fortress, built in 1558, once guarded against Ottoman incursion and served as the stronghold of the Uskoks — Habsburg-sanctioned irregular fighters and, depending on the telling, pirates, who used the town's brutal local bura wind (among the strongest sustained winds anywhere on the Adriatic) as a genuine tactical advantage against larger, less manoeuvrable enemy ships. The fortress today houses a small museum on Uskok history, and the wind that once served them still makes Senj one of the more bracing stops on the Adriatic coast road.

The small village of Smiljan, near Gospić in the county's interior, is where Nikola Tesla was born in 1856, the son of a Serbian Orthodox priest, in a modest house that stands today as the centrepiece of the Nikola Tesla Memorial Centre. The complex includes the reconstructed birth house with period furnishings, the adjacent church where Tesla's father preached, and a separate exhibition building with hands-on demonstrations of some of Tesla's electrical principles, including a working Tesla coil demonstration. It's a genuinely low-key, unhurried museum experience, reflecting the quiet rural character of the surrounding Lika countryside rather than a major tourist production.