NORTHERN BURGUNDY, France — Deep in a forest of France's Burgundy region, a group of enthusiasts is building a medieval castle the old-fashioned way — that is, with tools and methods from the late 13th century.

Some of those working here are heritage trade craftspeople, others are ardent history buffs, but all say they share a deep respect for nature and the planet, and a desire to return to simpler times.

"This is a place you experience with all your senses," says Sarah Preston, communications director and guide of these grounds known as Guédelon Castle. "As soon as we walk onto the site you smell the woodsmoke. There's something so evocative about these sites and sounds."

Just as she speaks, a horse cart rolls past carrying wood. Tapping from stonemasons rings out in the distance.

Once beyond the entrance barn doors, visitors plunge into a bygone age. There are no mechanical sounds, no motor engines — and cellphones must be turned off.

The idea to build Guédelon was born in 1995 among three friends, residents of the area, who are also history buffs and nature lovers. One of the three owned a nearby 17th century château and was involved in work to restore different castles in the area.

"But we thought, how amazing would it be to actually build a castle from scratch?" Maryline Martin, CEO and a co-founder of Guédelon, told public radio station France Culture last year.

After finding and purchasing the original 27 acres of land in a forest near a centuries-old abandoned quarry and water (necessary ingredients for any medieval construction site), the co-founders got a construction permit and, in 1997, laid the first stones.

Martin said the project is all about highlighting nature, history, archaeology and heritage skills. An advisory committee made up of archaeologists, historians and castle experts is associated with the project.

Martin said Guédelon is an example of experimental archaeology — which is a way to research how people did things in the past by trying to imitate them. It's about "building to discover," she said.

The builders use the examples of other medieval castles in the area, as well as descriptions in old manuscripts and books.

The workers are all dressed in medieval clothing, except for sturdy contemporary footwear and sometimes helmets mandated for a modern construction site.

The smell of fire and a clanking sound are coming from a nearby blacksmith's shop. That's where 20-year-old Matisse Lacroix is forging the tools needed to build the castle. Sparks fly as he pulls a cord that operates a large bellows.

Lacroix says the furnace temperature is around 2,000 degrees Fahrenheit, "so the iron is soft and malleable and I can make these nails." He bends and shapes pieces of iron into nails, and taps a decorative design into the square head of each one.

Part of Guédelon's mission is pedagogy, according to Preston. And during NPR's visit, a group of fourth-graders are at the site. They watch Lacroix pound the glowing red rods.

The craftsmen stop their work to explain what they're doing to visitors as well as train young craftsmen in heritage skills.

NPR asks the kids if they'd be interested in doing such a job one day. "Yes," says one boy. "I've always wanted to be a stone carver."

"Not me," says another. "I'm gonna be a YouTuber."

That learning aspect of Guédelon is one reason its construction is taking so long. The owners say the project is meant to discover and pass along skills and knowledge from a 13th century work site.

Workers stop their tasks several times a day to answer questions from visitors — as part of the job.

There are six turrets completed as well as a protective wall and inner living castle with a chapel. Preston says in medieval days the speed at which you finished a castle all depended on one thing: money.

It is hard to tell what the price tag may be for a medieval-style castle these days; the owners say they don't really know what the final costs will be.

Preston said they initially financed their work through donations and some European Union funding. Now the château is financed through more than 300,000 visitors a year (paying between 12 and 15 euros each), which she said generates about 5 million euros ($5.25 million) a year that largely covers pay for 100 staff members.

Twenty-four-year-old Simon Malier, who makes furniture for the castle, says he had a life-changing trip here as a boy. "After visiting with my grandparents, I wanted to be a sculptor in the medieval world since I was about 14 years old," he says.

A lunch bell rings out, just like olden days, and workers take a break.

There are all kinds of projects to recreate the kind of village that would have existed beside a castle like this 800 years ago.

A garden grows plants indigenous to the area in the Middle Ages.

"We grow only medieval plants," says Antoine Quellen, who works in the garden two days a week. "So that means we don't have tomatoes, we don't have potatoes, because those came from South America much later."

He says people ate a lot of grains back then. The indigenous plants are hardier and help preserve the land and soil, as they have a kind of genetic memory of place in their germ cells, he says.

Geese wander the grounds. They would have provided food in medieval times. "Don't get too close to them," warns Quellen, "they can pinch. They're better than guard dogs."

Half a dozen stone masons work near the quarry. Tendra Schrauwen, a 29-year-old from Belgium, says Guédelon is one of the few places in the world you can practice this craft using traditional methods and old tools.

"Our job is to cut stones in perfect geometrical shapes," he says. "For window, doors, chimneys, staircases, stone by stone."

He says it's all about teamwork. "The stones are very heavy. It's very dangerous, you can damage your body. So the most important thing is to work in a team."

Schrauwen says most people who work at Guédelon have a diploma in one of the heritage skills or work experience. They are paid workers, not volunteers.

"The charm of the skill is really to build by hand," he says. "There are no pneumatic hammers here. Everything is done by hand." By hand, and using old-fashioned tools, and motorless vehicles and mechanisms.

Teams of two and three masons struggle to roll big stones onto carts to transport them.

To lift the tons of wood and stone needed to finish the castle's outer walls, two men walk inside a contraption that looks much like a giant hamster wheel. It's a kind of medieval crane with a central axle and ropes. Known as a treadmill crane, it can pivot and raise or lower materials, depending on which way the workers walk inside it. The only modern addition at Guédelon is a safety brake.

Guillaume Glotin is one of the workers turning the hamster wheel. He says the treadmill crane can lift 1,000 pounds.

Glotin is part of the mason team finishing the castle walls. He's been working here 17 years, starting when he was 22. "You could say I've had a medieval career," he says, laughing.

He says he's extremely proud of what they've accomplished, and many people have come eager to learn.

Some of Guédelon's craftspeople have gone on to work on the restoration of Notre Dame Cathedral. Communications chief Preston says when the Paris cathedral caught fire in 2019, the phones in the off-site offices of Guédelon rang off the hook. "This castle is a known source for medieval building skills and knowledge," she says. "And those rebuilding Notre Dame needed advice."

Painter Claire Piot is mixing colors in a stone bowl. She's painting the chapel and bedrooms of the castle, using colors made from minerals found right here.

"We use some ochers, some clays, some soils, charcoal, lime — things like that and we can make 15 colors," she says.

Cylindrical towers of the castle have slits for shooting arrows, known as arrow loops, which are spaced to avoid dead angles. "These arrow loops are a bit like modern security cameras," says Preston. "They're a way of seeing out without being seen."

Preston says many of the defense features at Guédelon were brought back from the crusades. But she says it is being built to be a modest nobleman's castle, not a royal château. That means no drawbridge, for example.

Thirty-year-old Charles Teixido is hewing a log with an ax. The hollow chopping sounds ring out through a forest alive with birdsong. Teixido is a carpenter apprentice at Guédelon after changing careers from being a chef.

"I wanted to create something more durable," he says. "So now I'm still making something creative, but it will stay forever. What we're building here is going to stay maybe for 2,000, 3,000 years."

Teixido says climate change has proved that human beings must respect the planet. He believes the way they're working at Guédelon is relevant for a more sustainable future. After working here, he says he wants to go into building energy-efficient housing. "The future is low tech," says Teixido.

As for Guédelon's future, the builders say it could take 10, 15, even 20 more years to build, but they're OK with that. It's not about finishing the project, they say. It's about the things they learn and discover while building.