The presense of a tunnel had long been suspected at Teotihuacan. In 2003, heavy rainfall caused a section of the ground to sink, right in front of the Temple of Quetzacoatl. However, it took until last year to raise the funds and assemble a team of world-class archaeologists to investigate the site. Last month, after eight months of digging, they finally reached the roof of the tunnel. What they found next astounded everyone.
The Teotihuacan Archaeological Zone lies just 50 kilometers (31 miles) north-east of Mexico City. It was made a UNESCO World Heritage site in 1987. Teotihuacan translates as 'City of the Gods'; but that was a later moniker, given to it by the Aztecs, who found the majestic ruins in the 1300s. It is still an impressive area now, with little imagination needed to picture the city in its heyday.
No-one knows for sure who did live there. The Nahua, Otomi or Totonac tribes are all strong contenders. Teotihuacan was built around 200 BCE and was abandoned in the 7th or 8th centuries CE. The population, of approximately 200,000 people at its height, left behind a wealth of architecture, there are also plentiful murals depicting the myths, legends, gods and meteorology of the day. Not to mention lots of ceramics and other physical evidence of the inhabitants of this once great city.
Some of those mysteries may be about to be solved with this week's announcement from the National Institute of Anthropology and History (INAH - Instituto Nacional de Antropología e Historia). Using cameras lowered through the roof of the tunnel, archaeologists were able to glimpse one large chamber, with two smaller ones branching away. This is in addition to the tunnel itself which, in a scene reminiscent of an Indiana Jones plot, had been sealed with huge rocks hurled into it.
Speculation is rife that this is the last resting place of whomever ruled Teotihuacan. Sergio Gomez, one of the archaeologists working at the site, has spoken of the thousands of jade items, precious stones, shells and pottery seen in the chambers. There are also ceramics, which are of a style never encountered before. He concluded, "There is a high possibility that in this place, in the central chamber, we can find the remains of those who ruled Teotihuacan."
However it will be two months, at least, before the excavation team make it into the chambers themselves. No-one wants to damage the site any more than is necessary to access it, so progress is undertaken painstakingly, at a snail's pace.
It's a case of watch this space, but, in the meantime, enjoy the pictures provided by INAH.