If there is one river that defines Europe in terms of landscape, history and economy, it is the Danube, a 2,850 kilometre ribbon of water that flows from the Black Forest in Germany to the Black Sea in Romania. Some 470 km of its course make up a significant part of Bulgaria's northern border – and of its history, economy and life.

The connection between Bulgarians and the Danube is centuries old. Bulgaria appeared when the southbound people of Khan Asparuh crossed the river in the late 7th century. In the centuries that followed, the Danube protected the Bulgarians from invasions from the north and served as a vital link to Central Europe and Russia. In the 19th and 20th centuries, a steady stream of European innovations, from modern technologies to the arts and media, would reach Bulgarian lands via the Danube. The prosperity and progress of these times can still be seen in the elegant, if somewhat dilapidated, buildings that still dot Bulgaria's Danube ports and towns.

Sadly, the decline of the river's importance in international trade in the late 20th century and the collapse of Bulgaria's Communist-era planned economy led to a steady decline in the region. Today, few people brave the bad roads that lead to the Bulgarian Danube to discover its wealth of sights and experiences. But if you do, you will be rewarded with an often otherworldly landscape of sheer cliffs and river islands, Roman, medieval, Ottoman and modern ruins, exquisite fin-de-siècle architecture and macabre stories of political persecution. Here are some of the highlights.

The mouth of the Timok

At the very beginning of the Bulgarian Danube, the Timok river joins it, forming the last few kilometres of the border between Bulgaria and Serbia. Changeable and beaten by the flows of the two rivers, the patch of land that makes the beginning of the Bulgarian side of the Danube is covered with sticky mud that takes on strange shapes, sometimes imitating the colours and contours of rocks. The surrounding landscape is idyllic. Thick reeds cover the bank, where trees lower their branches to the water, and only the occasional fishing boat or barge disturbs the peaceful surface of the Danube.

Ottoman Vidin

Vidin, the first major Bulgarian town on the Danube, is justifiably proud of its place in Bulgarian medieval history – in the 1300s it produced the country's last medieval dynasty, the Shishmans. It was also the last piece of Bulgarian land to fall to the Ottomans in 1396. After Liberation in 1878, the town became a major economic and commercial centre, as evidenced by the number of beautiful fin-de-siècle buildings, the grand churches and the synagogue, and the magnificent riverside garden.

Few people realise, however, that Vidin is arguably the best preserved Ottoman town in Bulgaria. Look closely and you will be astonished at the number of buildings that have survived from that period – from the town's citadel, Baba Vida, whose latest layout was created by the Ottomans, to the preserved parts and gates of the outer walls of the Vidin fortress, most notably the magnificent Stamboul Kapi Gate. There is an elegant 19th-century mosque and a fine library next to it, the former telegraph office, a cross-shaped military barracks and a beautiful mansion that used to be the seat of the Ottoman governor and now houses the local archaeological museum.

Botev's landing, Kozloduy

One of the most sublime moments in Bulgarian national history took place in an unassuming part of the Danube bank, at Kozloduy.

In April 1876, the Bulgarians living south of the Stara Planina and around Tarnovo rose up against the Ottomans. Hristo Botev, a young poet, journalist and revolutionary living in exile north of the Danube, gathered a group of enthusiastic emigrants and seized an Austro-Hungarian steamship, the Radetzky, forcing it to land at Kozloduy. From there, Botev and his men moved south, trying to incite the Bulgarians to rebellion. They failed. Almost all of them died in skirmishes with the Ottomans, including Botev.

But the memory of their landing survived. The first memorial to Botev and his men in Kozloduy was erected in 1878. The stone monument you see today was erected in 1939.

The most interesting thing here, however, is the... Radetzky steamboat. It is an almost exact replica, built in the 1960s, of the original boat, with massive donations by Bulgarian schoolchildren.

Magnificent Roman ruins at Gigen

When the Roman Empire was at its height, it maintained a defensive line of fortresses and cities along the Danube to protect itself from barbarian raids from the north. As the empire declined and shrank, many of these were abandoned.

In the village of Gigen you will find the fascinating and mostly empty remains of one of the largest Roman cities along this part of the river. Ulpia Oescus began as a Roman military base in the 1st century AD. A century later it had become a major commercial and religious centre, complete with paved streets, elaborate temples, workshops and houses. In 328, the Emperor Constantine himself visited to inaugurate a bridge the Romans had built over the Danube.

By the end of the 6th century, Ulpia Oescus had disappeared. Today, thanks to partial archaeological research, the columns and pediments of its buildings lie among the overgrowth – a melancholy picture that will be a highlight of your Danube journey.

Macabre Belene prison

Between 1944 and 1989, Bulgaria was a Communist country. For most of that time, one name was whispered with particular dread: Belene, the infamous political prison camp.

The camp opened in 1949 on the largest island in the Bulgarian Danube – Belene or Persina. In the decades that followed, the prison would open and close several times, holding people the Communist government considered subversive – former opposition leaders, delinquent Communists, anarchists, peasants opposed to the forced collectivisation of farming land, students and even young people keen on western fashion. The last prisoners were about 500 Turks who resisted the forced Bulgarianisation campaign in the 1980s. Many prisoners did not survive the harsh conditions of the camp.

When Communism collapsed, the Bulgarian society was eager for some justice, but not a single official or guard was convicted.

Today, a modest memorial marks the remains of the political prison. There is still a functioning prison on the island of Belene, so visits are only possible on special days organised in advance by the Belene Island Foundation.

Vibrant Svishtov

Svishtov is a breath of fresh air after the gloomy atmosphere of Belene. Its centre, dotted with turn-of-the-century houses, is livelier than you might expect for a place of its size, thanks to the students of the Academy of Economics, the country's first business school. Commemorative plaques and statues of prominent Svishtov natives, such as the author of the national anthem, are scattered throughout.

The town's most famous son was the satirical writer, Aleko Konstantinov. His house is a museum where you can see a macabre exhibit: the writer's embalmed heart. It was pierced by the bullets that killed him incidentally, in 1897, when he sat next to another man, who was supposed to be the target of the assassination.

The emblematic sight of Svishtov is the 24-metre-high clock tower, built in 1763, which still keeps time with a mechanism made in Austria in 1890.

Ruse: past and present

Ruse, Bulgaria's largest city on the Danube, is a showcase of magnificent fin-de-siècle architecture from the period between the Liberation of 1878 and the Second World War, when Ruse was known as Little Vienna. It was from here that all sorts of Western ideas, businesses and products entered the Bulgarian lands: modern banking and street lighting, printing, the telegraph, town planning, shipbuilding, weather stations, modern art and much more.

Some of the most outstanding buildings in Ruse are the Dohodno Zdanie building (or Inland Revenue Building, the peculiar name stemming from the building's function: its property was to be rented out and the rent used to finance municipal projects), the elegant Freedom Monument designed by the Italian sculptor Arnaldo Zocchi, the State Boys' Gymnasium (now a secondary school), the Old Music School and the building that now houses the Ruse History Museum. The highest concentration of buildings from this period is along Alexandrovska Street, Slavyanski Boulevard and around the History Museum. Some are beautifully preserved, while others are in various stages of decay. Together they create a stunning urban landscape unlike any other in Bulgaria.

Tutrakan sunsets and soups

Tutrakan is off the beaten tourist track, although visitors swear by the uniqueness of its sunsets as the sun disappears behind the river. But Tutrakan's town centre has some beautiful buildings from the turn of the 20th century and the fishermen's quarter by the river does its best to preserve the spirit of the bygone days when the town was an important fishing centre. It was home to the first fishing cooperative in Bulgaria, founded in 1907, when half the town's population subsisted on fishing.

The fishermen and their families still live in their traditional houses. The area has grown organically along the riverbank and is now the only authentic fishing community along the Bulgarian section of the Danube.

Tutrakan is also the best place to try a dish that is offered in every Danubian town: fish soup. The local fish soup is considered superior to all others as it is made from at least five (up to 14) different species of fish, always fresh.

Srebarna birdwatching

If you look up Srebarna Lake on Google Maps, you will be surprised at how small it is. But for the thousands of migratory birds that settle here to spend the winter or summer, this patch of shallow water is something they would never miss from the air.

Danube pelicans are Srebarna's most famous residents, along with pygmy cormorants, ferruginous ducks, Eurasian spoonbills and the only mixed nesting colony of several species of herons and egrets in Europe.

In winter, Srebarna's population changes as birds from northern Europe arrive to spend the season in the milder climates of the Lower Danube: greater white-fronted and grey geese, Eurasian coot and mute swan, and a variety of ducks.

In total, about 100 species of birds live in Srebarna throughout the year. They can be observed from a designated bird-watching centre and a 20-kilometre eco-path.

In 1977 Srebarna became a biosphere reserve and in 1983 it was included in the UNESCO World Heritage List.

Silistra surprises

The last town on the Bulgarian section of the Danube offers a pleasant end to the journey along this stretch of the river. Like Vidin, Silistra has a beautiful riverside garden. Among the greenery and modern sculptures are the remains of ancient Durostorum and medieval Drastar – a basilica and some elaborate fortifications. The surrounding streets are a charming mosaic of neo-Baroque and neoclassical houses from the late 19th and first half of the 20th centuries, and on a nearby hill is an Ottoman fortress – the second best preserved on the Bulgarian Danube.

The most surprising sights in Silistra are two tombs. The first dates to the Late Antiquity and is richly decorated: an array of birds and portraits of the owner, his wife and their servants are painted on its walls. The second belongs to a prominent Jewish scholar who saved Silistra from a cholera outbreak in 1828-1829 by imposing a quarantine, but died of the disease himself. The symbolic tomb of Rabbi Eliezer Papo is now a Jewish pilgrimage site.