About 40 kilometres from the modern Mexico City you can find Teotihuacan, a pre-Columbian city, which flourished between 100 BC and 750 BC. This place, compared to the others of the period, was really gigantic and hidden inside the royal tombs was found a lake of mercury.
In 2003, in fact, two archaeologists of the National Institute of Anthropology and History of Mexico found a secret tunnel leading underneath the structure. Inside, despite the expectation of finding gold and wealth, crocodile teeth, jaguar sculptures, necklaces made of human teeth and much more were found. Unpublished archaeological findings are still found today.
The strangest discovery was, however, a miniature mountain landscape with pools of liquid mercury that apparently represented lakes. The walls of the tunnel were carefully infused with powder pyrites (also called gold of fools) to reflect mercury, creating a sort of “reflective effect” as if the place were surrounded by stars.
According to experts, this tunnel – which has been hidden for 1800 years – could represent a sacred river in the underground world leading to the royal tombs. Mercury was rare in ancient Mexico and difficult to extract; this lake could also be served as part of a ritual according to experts, but since no real graves were found in the hidden tunnel, researchers were unable to identify the purpose of the structure.