Mystery on the Danube

Kilometre Zero, on the brink of the Black Sea, is as gloomy as it sounds. An old, abandoned lighthouse marks the spot where the Danube begins. The scene seems too desolate to hold such significance for Europe's most romanticised river, yet it feels rewarding to reach this remote and mysterious site.

Some say the Danube starts in Germany, where the water springs from a source in the Black Forest; however, unlike most other rivers, it is measured upstream from the mouth, which is in Romania, almost 3000 kilometres away.

At this starting point, in the rundown town of Sulina, a small black-and-white "0" sign stands on a patch of grass. Anywhere else, there would be a grand monument, a souvenir shop and a queue of tourists taking photos. But this unremarkable sign is barely noticeable and the lighthouse has not been maintained for decades. Built in 1887, the masonry tower balances on the remains of a pier, accessible only by boat.

The 40-odd passengers on River Cloud II are the only travellers out here on a Friday afternoon. What's more, we haven't seen another boat all day. It's a far cry from the buzz of Budapest, where most people have boarded, or Amsterdam, where the ship set sail three weeks ago. This is truly off the beaten river. The Danube is also getting longer: as it carries sediment into the sea, it expands about 50 metres each year. This means that the rest of the waterway, past the official zero marker, is measured in the negative. A new lighthouse, constructed 11 kilometres further down, is counted as minus-11 kilometres.

According to historian Gerrit Aust, on-board River Cloud II for its 10th birthday cruise, although the actual mouth of the Danube has moved out far into the sea, Kilometre Zero remains symbolised by the rusty old lighthouse. As we sit on the top deck discussing the accuracy of these measurements, Captain Mihai interrupts. About one year ago, he says, a swimming race was held and the winner was to be greeted by television cameras on the shore. Preferring a more picturesque setting, the town's mayor apparently moved the "0" sign several metres to a spot in front of the elegant St Nicholas Church.

"So nobody is really sure where the river starts," the captain shrugs.

For many cruisers, arriving at this grey area is the fulfilment of a life's dream to complete the whole length of the Danube. On my sailing, a German couple reveal they have taken three separate holidays to cover one end to the other, while a woman from Melbourne has booked the three cruises back-to-back so she can "do the Danube" in one go. Others simply want to see a different way of life in countries they would probably never visit by land: Bulgaria, Hungary, Serbia, Romania and the border of Ukraine.

When I board halfway through the voyage, people are still raving about their visit two days ago to Belgrade's White Palace, formerly used by infamous presidents such as Tito and Milosevic, and now home to Crown Prince Alexander. The mansion hosted an exclusive concert for River Cloud II, as well as a no-holds-barred tour that was the highlight for many. Australian passengers gush about sitting in the stained chair where Tito had his hair dyed and literally touching a Rembrandt in the prince's study.

On a shore excursion in Constanta, founded around 600BC, a tour of the National Museum is similarly unrestrained. In the former City Hall, the museum houses one of the most important collections from the Roman era and most of the artefacts are displayed freely, not encased in glass or roped off from visitors.