After designing and running a workshop on urban biodiversity where I learned a lot about city bats, I now see them all the time. And can recognise species I didn't know.
For example today I found a wing of a common Noctule (la : Nyctalus noctula, fr : la Noctule commune, de : der Große Abendsegler) in the street! Pretty cool.
They're Vienna's biggest bats, and they're pretty common overall.
The photo is slightly 'gory', since it's really just a wing. And not in super good shape even.