On Donauinsel you can run a marathon by just running around the island. The thing is, though, it is only about 100 meters wide so you will be running back and forth on the same route.

And at each top (or so I am told), you must dodge stark naked people bathing, biking, and skating.

But on this windy winter’s day, the Donauinsel was asleep, save for a few kids playing soccer, a few seagulls taking a stroll, and a few rays of sunlight. And we. 
(Donauinsel, Vienna, Austria; February 2017)