I consider the Danube Tower to be no less an attraction than the Hundertwasser house, if you climb to the observation deck, or even better, sit in a rotating cafe with quite reasonable prices and beautiful views: the Danube with recreation areas, parks, new modern areas, even the Viennese forest is a little visible. Vienna is well visible in the direction of the center, it is easy to find St. Peter's Cathedral.Stefan and use him as a reference point. Fans of extreme sports can jump from the tower. I was even scared to watch others jump, but walking in the park around the tower was a great pleasure. You can also take a steam train ride through the park, the stop is next to the tower. Of course, if you only have 2-3 days to Vienna, then they will barely be enough for the Ring and museums, but if possible, I highly recommend visiting the Danube Tower on a clear day.