Secrets of the Lower Danube: Serbia to Hungary with Iron Gates

Situated along the famed Orient Express, where the Danube and Sava Rivers meet is Belgrade, one of the Danube's four riverside capitals. This is one of the world's oldest continuously inhabited cities—a place sieged, razed, and bombed by outsiders trying to control it. Today, the one-time capital of Yugoslavia is a thriving hub of government, finance, and urban renewal of many former communist-era districts. It is home to the Church of Saint Sava, one of the largest Orthodox churches; the famous Nikola Tesla Museum; Kalemegdan Fortress; and more.

A stronghold during Roman and Byzantine times, the eastern Serbian village of Golubac is surrounded by fascinating archaeological sites and imposing Golubac Fortress, gateway to Đerdap National Park and the Iron Gates gorges. Although the medieval fort had 10 defensive towers, it was attacked repeatedly over the centuries, changing hands between the Turks, Bulgarians, Hungarians, Serbs, and Austrians. Today, Golubac Fortress is part of Serbia's declared Immovable Cultural Heritage of Exceptional Importance, attracting thousands of visitors from around the world each year, while Golubac village is a popular destination for fishing, hiking, and sailing.

Located in the Veliki Kazan gorge, a section of the famed Iron Gates in Đerdap National Park, is Donji Milanovac, whose peaceful Serbian beauty is breathtaking. So much so, in fact, that filmmakers flock here, earning it the nickname of "Serbian Hollywood". Nearby, archaeologists have unearthed sculptures, weapons, and tools up to 9,000 years old that bear witness to an advanced Stone Age civilization—Lepenski Vir, one of the oldest settlements in Europe.

Sitting on the right bank of the Danube, the site of the eastern Serbian town of Kladovo has been inhabited since the Early Bronze Age. Today, Kladovo is popular for its beaches, wine trails, cuisine, and adventure activities, but the allure of the ancient past remains as strong as ever. This is where Roman Emperor Trajan built his legendary bridge across the Danube, and where the Romans also constructed Diana Fortress in the 1st century. Part of a vast defensive system along the empire’s border, Diana included a military camp, watchtowers, granaries, and even a civilian residential area.

Near the Serbian border, Croatia's easternmost city is known for its grit. During the War of Independence in the 1990s, it was almost completely destroyed after an 87-day siege. Vukovar rebuilt, and the Old Town is once again a magnet for guests from around the world. Highlights include the town's famous water tower, whose battered structure is a symbol of the proud Croatian spirit; the poignant National Memorial Cemetery of the Victims of Homeland War, the nation's largest mass grave; and elegant Eltz Manor, the 18th-century Baroque home of the Vukovar City Museum.

Kalocsa is one spicy city! The self-proclaimed "Paprika Capital of the World" is one of Hungary’s oldest cities, filled with historic buildings and quaint shops (selling paprika—what else?). Highlights include the 200-year-old Folk Art House, where local female artisans still paint furnishings, eggs, and other items in the traditional Hungarian way; the Paprika House, a museum dedicated to the legendary Hungarian spice; and the Archbishop's Palace with its 150-thousand-volume library of ancient books and manuscripts.

One of the most beautiful cities in the world, the wonders of Budapest rise up along both banks of the Danube in a truly impressive way. Along with Heroes' Square with its Tomb of the Unknown Soldier, awe-inspiring Hungarian Parliament Building, and the lavish Castle District with photogenic Fishermen's Bastion, the city is home to a captivating Jewish district and the second-largest synagogue in the world, an intricate underground cave system, and some of Europe's most famous thermal baths.