An interesting public art piece

From John Desmond, Downtown Denver Partnership, via an e-list:

In the Downtown area of Denver, we have a public art piece call the sound wells. The sound wells are located below grade with a sidewalk grate above each one on the sidewalk of a street that connects the Denver Performing Arts Complex with the 16th Street Mall. I believe there are 5 of them. Each sound well has a speaker system and taped recordings of about 100 different sounds, including running water, a subway, bird calls, a dragon(!) and other unique sounds. Many people at first think there is actually a subterranean use generating the noises. It is popular with children and a great surprise to visitors once the source is explained. The sound wells have been in operation for over 10 years.