The Mystery of the Chirping Mayan Pyramids.
If you are lucky enough to find yourself alone in front of the Mayan pyramid of Kukulcana in Chichen Itza, an acoustic miracle is available to you. Clap your hands in front of the pyramid's steps, and it will answer you with the cries of the sacred Quetzali bird. And if you listen to the footsteps of rising people, you will clearly hear the sound of falling raindrops.
Most likely, the sound of "raindrops" is created by the interference and diffraction of sound waves arising from the steps on the grooved surface of the steps. And the sounds are best of all heard at the bottom of the pyramid. And cavities inside the pyramid transform usual claps into chirps of the sacred bird of Mesoamerica.
Forbidden History
