Chichen Itza in Mexico is one of the best preserved ruins of the Mayan civilisation. Though it is now a bit of a tourist attraction, it was once a focal point for the Mayans. It is home to a large pyramid called El Castillo which has been the subject of many archeological surveys and digs and has, like many ancient monuments and structures, many theories surrounding it, from the faintly believable to the outright incredible. The geometry of this place is very interesting and it's fascinating to see the various design elements that are built in - for example at the equinoxes of Spring and Autumn, the sun can be seen to project a pattern onto the steps which line up with huge carvings of snake heads. The illusion for a few hours is that of a massive snake running up the length of the pyramid.

Equally interesting is the use of sound at this fantastic ruin. In fact some research has been done to suggest that the entire site was built as a place of worship for either the rain god Chaac and that the whole ruin can be thought of as a huge musical instrument. Indeed the sounds at this place can be very strange indeed. For example, standing at the base of the pyramid and clapping can yield a rather peculiar chirrup echo which first ascends and then falls much like the sound the native bird quetzal makes. Another peculiar and even eerie sound is if you sit at the base of the pyramid and listen to the footsteps of the other visitors as the climb the pyramid. It sounds as if raindrops are falling into a bucket as visitors get closer to the top of the pyramid.

Some of these clever acoustic tricks can also be found in the Chavin civilization and more specifically in the Chavin de Huantar ruin which is in Lima. The temple here is believed to be the religious centre of the Chavin people and also has some very peculiar acoustic properties. For example the drainage system created around the temple include some canals that are routed under the temple which would create a roaring sound during the rainy season, making the temple sound like a jaguar, no doubt to either honour the animal or scare worshipers into believing that the gods were actually talking. Some scientists have postulated that the intricate chambers at Chavin were specifically designed to funnel sounds and echos in terrifying ways which could be used to trick an unsuspecting populace into believing that the priests could actually communicate with the gods and to continue subjugating the population so that the religious leaders could maintain power.

There is much we don't know about the old civilisations, but it's fun to look at the discoveries in the old sites and see just how skilled the builders were, even if the ultimate use of the sites was to scare people.