If it wasn't for the moles, English archaeologist Stuart Wilson may never have discovered his find of a lifetime.

Back in 2002, when Wilson was an archaeology graduate, a farmer investigating some molehills in a field near the border between England and Wales discovered something unusual. Scattered about the freshly dug mounds of earth were what appeared to be shards of pottery.

The farmer reported his find to the Monmouth Archaeological Society, which tipped off Wilson to head out and take a look. Upon his first investigation, he discovered what appeared to be the remains of a wall. Despite this promising start, it would be another two years before he would have the chance to fully uncover the site's secrets. All it took was a giant financial leap of faith.

In 2004, the 4.6-acre plot came up for auction. Instead of buying his first house, Wilson decided to throw down a winning bid of 32,000 pounds (about $39,000) and purchase what visually appeared to be little more than a beautiful, green field.

"I should have really bought a house and got out from my parents', but I thought: 'To hell with my parents, I will stay at home and I shall buy a field instead," he told the U.K. Telegraph. "People said 'you must be mad'."

Here's a video of the project:

Twelve years later, it's clear that Wilson's gamble has paid off in a very big way. After countless hours of digging and assistance from more than 1,000 amateur and professional archaeologists, the 36-year-old believes he has uncovered the remains of the sprawling medieval city of Trellech.

Trellech, settled in the 13th century, was an important urban center focused on the procurement of iron and the manufacturing of weapons and armor for the Welsh military. At one point, it featured a population of between 10,000 to 20,000 people, making it one of the largest medieval cities in all of Wales.

After being ravaged by civil war, disease and famine, the city was left to ruin sometime in the 17th century. Until Wilson's discovery, archeologists had yet to pinpoint its exact final resting place.

“Much more experienced people were saying the city wasn’t there but I was young and confident,” he told the U.K. Guardian. “If I was right the high street was right there in that field. It was a wonderful opportunity.”

Trellech city The remains of a large round tower discovered at the Trellech excavation site in Wales. (Photo: The Lost City of Trellech Excavation/Facebook)

To date, Wilson and his team have discovered several buildings, including a manor house with two halls and a courtyard, a massive round tower, fireplaces, a well, and artifacts from pottery to a neolithic flint knapping kit. Eventually, they hope to add an education center and turn the site into a tourist attraction. (Those interested in volunteering to get a little dirty can sign up to participate in some key excavations planned for later this summer.)

"Out of all the decisions I have made in my life I would say buying the field was one of the good ones," Wilson added to the Telegraph. "I have to say that even with all the problems that I have had or that may occur, it was definitely the right thing to do."

You can explore a 3-D drone overview of the site in the interactive video below.

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.