Here is a short video about the unexplained mystery concerning the Aztec Whistle. The Aztec Whistle is one of the scariest sounds you will ever hear. The Aztec Whistles release a bloodcurdling sound and are carved into grotesque looking skulls. This video is a little over 3-minutes long and provides some background on the Aztecs use for the whistles and a few examples of the Aztec Whistle.
Thanks to Unexplained Mysteries for creating and posting this video.