New York City of Sound

In 1999, New York-based sound artist Stephen Vitiello was awarded a five-month studio residency on the 91st floor of the World Trade Center. For his project World Trade Center Recordings: Winds After Hurricane Floyd, he taped contact mics to the studio windows, "picking up the sounds outside of passing planes, helicopters, storm clouds and traffic, the building itself swaying in the wind."
You can listen to a short NPR piece about the project (and find other sounds here); meanwhile, Vitiello was recently interviewed in Artkrush, if you want a bit more information.
But this reminds me of two other, related projects: 1) I read a review once in The Wire about a guy who taped contact mics to his window to record the sound of snowflakes hitting the glass – a recording which was then released on CD. Unfortunately, I can't find any information about this at all.
2) Extensive seismic readings were taken by Columbia University during the World Trade Center attacks of September 11th – the Precambrian bedrock of Manhattan was rumbling as the two towers collapsed, and this showed up on Columbia's seismometers. Sound artist Mark Bain then transformed this information into audio files, so you can actually listen to the wounded, melancholic howl of Manhattan as its two tallest buildings fall to the ground.
Ultimately, Bain produced "a 74-minute recording of the ground vibrations of the World Trade Centre's collapse and contiguous mayhem," The Guardian writes. "It certainly does not make easy listening. The piece begins with a low, disconcerting rumble and proceeds through a range of fluctuating sounds. Bain says the vibration of the towers as they were hit by the hijacked passenger planes sounds like 'tuning forks'." He then seems quick to add that he "sees nothing morally questionable in making an artwork out of the event."
"I guess I'm the black sheep," he says, "the anti-architect."
If you have RealPlayer, you can download a 2-minute excerpt.
Another vaguely related story, of course, is William Basinski...

(This post was extensively updated on 26 January. For more on urban soundscapes see Orchestra of Bridges, London Instrument, Sound Dunes, and – an old favorite – musicalized weather events).