You can take a day trip by boat from Vienna or Krems and explore one of the stops, such as Dürnstein or Melk. Boats run from May to late September. There are two boat companies that ply the Danube. Along this stretch of the river, bridges are few and far between. Old-fashioned tow ferries, attached to cables stretched across the river, allow a speedy crossing for people, cars, and bikes for a small fee.