For a brief part of my childhood, I immersed myself in the fantasy world of Dungeons and Dragons. (Yes, I know I am dating myself.) So, when I read about a network of centuries-old tunnels that opened last December, in Puebla, Mexico, I was instantly fascinated. And I am not the only one.

City officials tell us since small sections of the tunnel opened last December, 140,000 people have flocked to see them. "It's something new. It's part of our story here in Mexico and it's so interesting and important for us to know our history," said tourist Ana Karen Ramirez.

The tunnels are part of an underground history that the almost 500-year-old city is calling the "Secrets of Puebla". Serendipity, not scholarly research, is responsible for the discovery.

The tunnels are part of an underground history that the almost 500-year-old city is calling the "Secrets of Puebla" [Natasha Pizzey/Al Jazeera]

In 2014, a construction crew was building an underpass in Puebla. Initially, there were plans to build an overpass. But Puebla is a historic city and officials want to preserve it. In the midst of digging, a crew unearthed the remains of a dam and a tunnel.

A year later, this excavation project began. It's believed there are as many as 10km of tunnels, spanning from the 16th to the 19th centuries.

"You can have tunnels and caverns in lots of parts of the world," says Sergio Vergara, Director of the Historical and Heritage Centre of Puebla. "But here, the interesting thing is that these tunnels are under the city. That’s what makes this network important."

There is still so much that is unknown about the tunnels, including why they were built and exactly who used them. It’s believed the Spanish Conquistadors [conquerors] first constructed them in the 16th century.

A construction crew building an underpass in Puebla unearthed the tunnels [Natasha Pizzey/Al Jazeera]

Vergara says the newest sections of the tunnel date back to the 19th century. There are myriad theories about what the tunnels were used for. They include the possibilities that nuns and monks used them to move from church to church, soldiers rushed through them during battle and horses and people walked from house to house.

"The concept that people would move underground as part of their lifestyle, instead of above, gives you a new idea about how mobility was in the colonial time here," says Vergara. "You'd go from the indigenous areas to the Spanish areas, to the churches, the areas of power and to the battlegrounds and barracks."

Construction workers are excavating by hand and it’s a painstaking process, as you can imagine.

"When we got here it was all filled up, right to the top. We’ve had to empty out the muck, just with buckets, carrying on your shoulder and taking it up," says worker Leopoldo Barrientos Aranda. "There’s no other way to do it."

The workers have also unearthed artifacts such as bullets and buttons.

The city hopes that over the next 15 years it will be able to fully excavate the extensive network of tunnels. In the meantime, officials tell us there is such feverish interest in the tunnels that seven hotels are being constructed.

We are also told that the areas above sections of the tunnel that are open have gentrified. Once, the tunnels were urban lore, passed from generation to generation. Now, it seems, everyone is searching for a tunnel in Puebla.

The city hopes that over the next 15 years it will be able to fully excavate the extensive network of tunnels [Natasha Pizzey/Al Jazeera]

Source: Al Jazeera