Listen to the fountain bubbling at Ottoplatz; in front of the EASA building.
From a coloured monolith (about 10 meters high); water is pouring down into a small pool. Traffic can be heard in the back of the recording, too. Some people are passing by and talking - just have a close ear.
Download MP3 Springbrunnen am [...]

Especially in autumn and winter, you can find dozens of mallards (Stockenten) at Adenauerweiher.
Adenauerweiher is part of the Stadtwald (-Parc). Mallards are dominating this recording; but if you listen closely you can also hear the call of some tiltmouse. After 20 seconds or so you might recognize the breathing of a runner, too.
Download MP3 Stockenten [...]