Shh... the canyon's trying to rest.

{The photo's from Glen Canyon, not El Grande}

"Mounted at about ear level on tripods, microphones are capturing the sound of quiet at the Grand Canyon.

"The four microphones are attached to sound level meters and computers that will later screen out all manmade sounds, such as the chatter of hikers, the rumble of cars and the buzz of sightseeing planes and helicopters. All that will be left will be the sounds of nature: the wind in the trees, the chirping of birds, for example.

"Park officials are doing this because they need to establish the natural decibel level at the Grand Canyon before policymakers can decide whether the current noise-reduction regulations governing flights over America's most breathtaking natural wonder are adequate."

To listen to some ambient audio adventures, please refer to Quiet American.