This is because what people think is the Danube, well, isn’t.
In London, for example, you have the Thames winding its way through the very center of the city.
The Seine in Paris is similar. So people assume the unremarkable waterways at the heart of Vienna must be the famous Danube. But they’re not.
So what’s going on?
The map below shows you the main bodies of water in the city. The central district is marked in black. The Danube is the thick blue river running from NW to SE. As you can see, it crosses the upper part of Vienna, well away from the historical center.
It’s easy to understand how confusion arises because there are two river-like waterways skirting the edges of the center (the orange and purple lines). You’d expect one of them to be the Danube.
The river coming in from the west is the Wienfluss or River Wien. It’s relatively small and meanders past the summer palace (Schönbrunn) and along the eastern edge of the center through the Stadtpark:
Parts of the city (like the Naschmarkt) are built over it, so the Wienfluss is actually underground for some of its journey. It eventually joins another river (the purple line) at the NE point of the city center.
This second river is quite wide and is the one most often mislabelled as the Danube. It’s the Donaukanal or Danube Canal (though it’s best to think of it as a channel, not a canal).
Technically, it’s an arm of the Danube that forks off just after the latter enters the city in the NW. It rejoins the Danube proper on the SE side of town. There are bars and art installations (graffiti) along some of its bank, as well as a mooring point for sightseeing ships.
So why did they build the city away from the actual Danube?
The Donuakanal was the main arm of the Danube in the early days of Vienna. However, the river’s width and course often changed after floods. With time, the main arm shifted away, leaving the city perched on the edge of a slightly less impressive Donaukanal.
Of course, the waterways are now heavily regulated, so there’s not likely to be any course changes in the future.
To the NE of the Danube you can see another small waterway (the short green area): the Alte Donau or Old Danube. Again, this was also once a main arm of the river. The authorities eventually had enough of the floods and vagaries of the Danube, so in the late 19th century they put an end to it all.
They basically forced the Danube into its current route, and the “old” Danube was actually cut off from this new river. As such, it’s not so much a river in its own right, but more of a recreational lake. Here’s a photo:
Still with me? Because we’re not finished.
The main “actual” Danube was further regulated in the 1970s and “split” into two parallel arms where it passes through the city.
The southern arm is known as, well, the Danube, while the northern arm is the Neue Donau or New Danube. The artificial sliver of land between the two is the Donauinsel or Danube Island, a recreation zone and home to Europe’s largest free music festival. Here’s a view of it all from the Danube Tower:
How to find the Danube
Although it’s not conveniently placed in the centre, the Danube is easy to reach on the fast subway system. Once you get there, you’ll find walking and cycle paths more or less all the way along the river. In fact, a popular pastime among locals and tourists alike is to cycle along an extended stretch of the Danube through Austria and beyond (details here).
Line U1: Stations Vorgartenstraße (southern bank), Donauinsel (on the island) and Kaisermühlen VIC (northern bank). The next stop after Kaisermühlen is the station Alte Donau, which is ideal for visiting, um, the Alte Donau.
Line U2: Stations Donaumarina (southern bank) and Donausstadtbrücke (northern bank)
Line U6: Stations Handelskai (southern bank) and Neue Donau (northern bank).