I recorded a bunch of 2-minute(ish) audio files on my iPhone at intersections in midtown Manhatten, mapped them out in 3d space using the HTML5 audio API, and used the embedded Google StreetView API to move around the city.
The sounds fade in and out depending on where you are, and what you're looking at.
You can help! Make a short recording of the sound at a place in New York, add the details to the JSON in the file header, and upload the audio to audio/.
fontawesome, google, w3c