Was Maya Pyramid Designed To Chirp Like A Bird? Clap your hands in front of the 1,100-year-old Temple of Kukulcan, in the ancient Mayan city of Chichen Itza, and, to some researchers' ears, the pyramid answers in the voice of the sacred quetzal bird. A handclap at the base of Kukulcan's staircase generates what [acoustical engineer David] Lubman calls a "chirped echo"—a "chir-roop" sound that first ascends and then falls, like the cry of the native quetzal. To Lubman, the dimensions of Kukulcan's steps suggest that the builders intended just such an acoustical mimicry. The lower steps have a short tread length and high riser—tough to climb but perfect for producing a high-pitched "chir" sound. The steps higher up make a lower-pitched "roop."

Neat.