'Entrance to the underworld' is discovered in Mexico: Archaeologists uncover the 'back door of hell' in tunnels under an ancient church

Tunnels that the ancient Zapotec civilisation believed to be the 'entrance to the underworld' have been found beneath a centuries-old church.

Mitla, meaning place of the dead, was a city in southern Mexico known for its association with Pitao Bezelao, the Zapotec god of death.

But the Spanish arrived in the 16th Century and razed the city, building a church on the ruins of its most important temple.

A priest later wrote that 'the back door of hell' lay under the city – huge caverns believed to be the entrance to the Zapotec underworld.

But they were walled up, he said, and later excavations failed to find anything matching the scale of his description – until now.

Using non-invasive techniques, archaeologists recently revealed a series of chambers and tunnels beneath the city.

Five different sets of ruins were probed: the church group, the arroyo group, the adobe group, the south group, and the group of the columns.

Marco Vigato, founder of the ARX Project, which is leading the search, said: 'Some of the tunnels and chambers extend to a considerable depth, in excess of 15 metres.

'In the case of the south group, they're up to 30 metres deep – this is as far as the instruments can penetrate.

'One chamber under the Church of San Pablo Apostol measures approximately 15 metres long by 10 metres wide.

'It is possible that the tunnels, particularly those under the church group, extend further to the north, east and south.

'Possibly they connect to other geophysical anomalies identified under the other groups.'

If these are the tunnels of legend, the Zapotec kings may lie within.

Francisco de Burgoa, the aforementioned priest, paints a picture of the royal burial chamber in his 1674 text, Geografica Descripción.

He says the kings are interred 'richly dressed in their best attire,' with 'feathers, jewels, golden necklaces, and precious stones'.

Their bodies, meanwhile, hold 'a shield in the left hand and a javelin in the right, just as they used them in war'.

Two further caverns he describes contain a chapel, and a burial chamber for the Zapotec high priests respectively.

The final chamber, he says, leads to 'a dark and gruesome room' where 'they threw the bodies of the victims of the great lords and chieftains who had fallen in battle.'

Mr Vigato said: 'The Zapotecs believed the caves and the subterranean labyrinth under Mitla to be an entrance to the underworld, or Lyobaa.

'For this reason, Mitla was the centre of the cult of Pitao Bezelao, the Zapotec god of death and the underworld, and was for centuries the cemetery of the Zapotec kings and high priests.'

It's no coincidence that there was a void beneath the church altar.

Mr Vigato said: 'The church was built deliberately on top of the most important Zapotec temple at Mitla.

'It was a way of converting a pre-existing religious site and symbolising the triumph of the new faith.

'A significant portion of the ruins were incorporated into the foundations of the church, which was built with stones stripped from the ancient buildings.'

The underground tunnels were revealed using a combination of ground penetrating radar, electric resistivity tomography, and seismic noise tomography.

The first method uses radar waves to model the subsurface, while the second detects buried structures by measuring the flow of electricity through the earth.

Instead of electricity, the final method measures the speed at which seismic waves move through the ground.

Just how old the tunnels are is yet to be established.

Mr Vigato said: 'Natural caves in the area of Mitla have been occupied and partially modified by humans for thousands of years.

'The earliest evidence of crop domestication in the area of Mitla dates back almost 10,000 years.

'There is no indication at the moment as to the possible age of the tunnels under the church or the other groups of structures at Mitla.

'They may have been created by the Zapotecs, or they could be much older.'

He added: 'The findings from the geophysical scans will have to be confirmed with archaeological methods.

'This could determine the nature of the cavities identified under the site and whether they contain any artifacts of archaeological significance.'

You can learn more about the discoveries at Mitla at www.arxproject.org.