This is a soundwalk called Walk With Me and it is just under 10 minutes long.
To try the soundwalk, right click the download link and ‘save as’. Sync the downloaded file to you MP3 player of choice, wait until the next time it rains, and take it out with you. Put your headphones on, press ‘play’.
This soundwalk is best experienced in a not-too busy (but still urban) setting, in the rain. The rain bit is important.