Oh very well, it might not be the smallest one. But surely it is a small one.
Season's over in Vienna Prater of course. But like that, with almost no people at all walking the empty streets, Prater is very much worth a visit.
(Well, I should note that there was one place where even on this day - zero degrees Celsius, stiff northerly winds - quite some tourists frequented the famous fun fair: which was the Big Ferris Wheel place - Wiener Riesenrad - even though that one was closed too. Of course every tourist in his right mind should at least take one photo of Wiener Riesenrad; it would be scandalous not to do so, no matter what the weather is like.)
