Karlovac is a city in the northwest Croatia, 45 km southwest of Zagreb with a population of approximately 60,000.
Karlovac is located at the junction of 4 rivers; the Kupa, Korana, Mrežnica and Dobra, and is therefore known as "the city on four rivers" in Croatia. In fact, only three rivers flow through the city itself and the fourth, the river Dobra, is a bit on the outskirts. Because Karlovac is the home of one of Croatia's most famous breweries, natives also sometimes joke about the "fifth river" – the one made of beer.
The town plan is unique in Croatia as the historic town center is in the shape of a 6-pointed star, this being the design feature of the fortifications that surrounded the city. In fact,the town itself and surrounding fortifications were founded in the 16th century for the purpose of strengthening the area's defenses against the invading Ottoman Empire, and the star-shaped plan was a feature in many fortifications of the day, which made it impossible for attackers to attack a wall on one star "point" without being shot at from behind form another wall on an adjacent star "point". Later in time, after the Ottoman threat faded, the city walls were torn down and the moats surrounding them were emptied. Today only one small section of the original walls remains, while the former moats are now large parks and recreational areas.
While Karlovac isn't really a popular tourist destination in Croatia, being on the way from Zagreb to the coast makes it a convenient and nice place to spend a half day or full day trip, and who knows, perhaps more?
There are hourly or even half-hourly buses from Zagreb throughout most of the day, the journey takes 50 minutes and costs between 40 and 50 kuna.
Trains from Zagreb are also frequent (slightly less so than buses, every 2-3 hours), normal passenger trains (if not late, which can happen) take about an hour, and express trains take half an hour.
A trip by car on the A1/A6 motorway takes only about 20 minutes from Jadranski Bridge in Zagreb. From Rijeka it's about an hour ride.
The town is small enough to comfortably explore on foot, but the best way to get around is by bicycle.
There are not many shopping options. Modest shopping "malls" are Supernova (near the motorway toll station and Hotel Europa) and Karlovčanka (city center). Locals usually do more serious shopping in Zagreb.
Karlovac is the home to one of Croatia's two most popular breweries, and its Karlovačko beer which is a must try.
The main street is called Korzo, and together with Promenada (the adjacent part of the park) is home to many cafes and bars where you can enjoy sipping a coffee in the day or party on weekend nights.
As is the case with most of Croatia, rooms are available in private houses.
Almost every year one or more people drown swimming in Karlovac's rivers. Be very careful around numerous waterfalls and rapids which are often popular swimming spots.
Although minefields left over from the war have been cleared from the immediate vicinity of the city, if hiking off the beaten path in remote areas east or south of the city, pay attention to any minefield warning signs and do not proceed if you see any. As these signs are sometimes stolen, it's good to inquire about mine danger in suspect areas.