For much of its recent past, the gritty port of Rijeka didn't belong to Croatia at all, but Italy and Hungary. It's now its third largest town after Zagreb and Split, and a vital transport hub. Excited visitors sit atop Rijeka's Kavana Ri, resting their cold beer on its terrace overlooking their sleek Jadrolinija liner soon bound for idyllic Adriatic islands. They must wonder what they're leaving behind, a town whose main building is called Big Skyscraper, where Socialist blocks are stuck to Austro-Hungarian confectionery, a kind of Bratislava with boats.

Founded by the Romans, and Habsburg as early as the 1400s, Rijeka fell under Hungary in the late 1700s. The landlocked Magyars built a new harbour, baroque landmarks and sundry industries (including the world's first torpedo), though the nearest Hungarian town was 350km (217 miles) away. After the Habsburgs collapsed in 1918, Mussolini's men took Rijeka, then the Germans in 1943. Rijeka industrialised under Tito, rusted in the 1990s, but recent developments in transport infrastructure - the motorway from Zagreb, the road bridge from the nearest airport at Krk island where easyJet flies in to from June 2006 - may see a change in fortunes. The Gateway Project, signed with the World Bank in 2003 for an estimated €300 million, will see the Rijeka waterfront transformed in ten years. A new passenger terminal, a nautical centre and marina, and a link road with the Rijeka roundabout - and Zagreb and Budapest - will all be in place.

The tourist board has a dinky new office in Rijeka's pedestrianised high street, the Korzo. A few baroque façades fade behind modern shops and cafés. A short walk west is the main bus station, backdropped by the bizarre, two-level Capuchin Church. East, the Korzo ends at the local bus station and the so-called Dead Canal, actually pretty and pedestrianised. Its nearby continuation, the Rjecina, is the division between Rijeka and the former separate areas of Susak and Trsat. Between the wars, this stream was the border of Italy and Yugoslavia.

From here you can trek up the 538 steps of Stube Petra Kruzica to Trsat Castle (Petra Zrinskoga), notable for its panoramic café - or take the No.1 bus for a lovely hilltop stroll and take the steps back. Alternatively, you can turn left from the canal at Titov trg into Zrtava fasima and St Vitus' Church (Grivica 11, 051 330 897), a Venetian-inspired creation from the 1600s. Just above it stands the suitably stately Governor's Palace, commanding a view of the sea. Exhibits belonging to the History and Maritime Museum here (Muzejski trg 1, 051 213 578) are overshadowed by Alajos Hauszmann's sumptuous state rooms. Next door, the City Museum (Muzejski trg 1/1, 051 336 711) contains modest, temporary exhibitions in a modern, two-floor space. Overlooking these two buildings is the Natural History Museum (Lorenzov prolaz 1, 051 553 669), with an aquarium, geological displays and recently opened botanical garden outside.

Spinal Frana Supila leads from the museums towards Trg republike Hrvatske, with the University Library, which houses the Modern and Contemporary Art Museum (Dolac 1/II, 051 334 280, www.mmsu.hr).

Tourist information: Korzo 33 (051 335 882, www.tz-rijeka.hr).