Danube Cycle Path: Part I
One wonderful aspect of being in Vienna is the Donauradweg! The Danube Cycle Path runs through Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, and the Ukraine along the Danube river. It begins in the Black Forest and ends at the Black Sea, covering a total of almost 3,000 km.
In and around Vienna, the trail has a similar anatomy to the Charles River path in Boston. However, it continues in both directions, becoming more rural and interesting the further out one ventures.
There are several bike shops situated directly on the path that rent bicycles by the hour and by the day. The bikes can be taken along the trail straight from the shop without ever coming in contact with street traffic.
This is the one I've been riding: an Austrian brand, KTM. It's okay for exploring along the river, but for my own bike I'd want something a bit more classic and without the suspension fork.