Updated: Jul 21, 2020
I'm getting the "Lonely Planet" newsletters all the time and sometimes they publish rankings or reports about the best, biggest, loneliest, most most beautiful etc. places in the world. Lately I came across a report that said that Vienna was voted for the "GREENEST" City in the world - here is the link: https://www.bestcities.org/news/2020/04/22/the-worlds-greenest-cities/
That was very gratifying - but not a special surprise for me. When I introduce Vienna to visitors or create an itinerary for their time in Vienna I always try to point out the fact that Vienna is not only a treasure trove of first-class music, architecture and full of history and art, but that Vienna also has a strong "recreation factor". More than 50% of the area of Vienna is green or water - so it is quite possible to hike through woods, parks and fields for hours, or do any kind of sports you can imagine including golf, riding or sailing.
I personally am a rower and a runner and my favourite place to do this is the "Old Danube" quite close to the Vienna International Center with the UN - Buildings where I can easily bike or go with the Subway. I Also love to jog along the water which is very convenient at the 20km long completely green "Danube Island" between the "New Danube" and the Danube river stream.
In the past I have lived very close to the "Prater", a huge green area in the middle of the city that you can hike for hours through woods and meadows, where you can jog along the "Haupt-Allee" a 4,5km long avenue with chestnut trees, lie in the grass and relax in shadow of 100+ years old trees or delight you children with one of the many great playgrounds (including a hill with snow cannon where they can do sledging in winter).
West and south of Vienna you find the "Wienerwald", a huge area with woods and vineyards - and the "Heurigen" which are the typical Viennese wine taverns where they serve the local wine - but that's a different story. One on my favourite hikes is up to the "Leopldsberg", the outermost hill that descends to the Danube valley which provides the best overview over Vienna - a romantic place with a church and a little castle and a good spot for a man to ask his girlfriend if she wants to marry him - at least that was what I did after climbing the hill with her (and my dog)...