There's an island off the coast of Rome where locals have been living in cozy grottoes since the dawn of time.

The shores and fishermen village of Ponza -- the largest island of the Pontine archipelago, which sits offshore between Rome and Naples -- are dotted with cave dwellings cut into the ragged sea cliffs, offering stunning views.

These homes, fresh in summer and warm in winter, require neither heating or air conditioning. They're the island's gem, and now popular with vacationers.

Since the 19th century, locals have been emigrating abroad, mainly to the US in search of a new life. However, they've held on to their traditions -- which includes their traditional housing style.

One family to emigrate were the Avellinos. Luigi Avellino was the first of his family to leave Ponza at the beginning of the 20th century, initially going back and forth between the island and New York, before settling in the US permanently.

Attilio Avellino -- one of his nine children, and born on Ponza -- joined his father in the Big Apple in 1946.

But now, after decades in the US, their descendants are back on the island -- living inside their old casa grotta (cave home), which they've renovated to a modern standard.

Homes sculpted from the rock

Brigida Avellino, 70 -- Attilio's daughter -- lives with her daughter Loredana Romano, 44, in one of Ponza's most beautiful cave homes. It has thick, rough whitewashed walls, and a terrace with views of the uninhabited island of Palmarola. Couches, chairs, benches, stairs, beds, tables and cupboards are all cut out from the cave.

"These grottoes are part of our DNA and heritage -- each time a new baby was born the parents would dig another room inside the cliff, expanding the cave home," Romano tells CNN Travel.

The younger generations moved to Ponza in 1980 when Attilio Avellino had a heart attack in New York. His doctor there recommended fresh air, no smog and a peaceful place to live -- so the family returned to his birthplace.

Avellino has fond memories of her childhood in the US. While Ponza offers a slower-paced lifestyle, she misses the Big Apple's hectic world.

"I have learned that you can take a girl away from the big city, but you can't take the big city away from her. It sticks, even if I've been back in Ponza for decades now," she says.

Avellino moved to New York alongside her mother in 1955 when she was two years old. Her father and grandfather were already living and working there, alongside her uncles and aunts.

"I worked in a steel factory for 22 years. I loved the chaos, the traffic, the buzz, the noise and all those people rushing to work at all times of the day," says Avellino now.

Her father and grandfather did all sorts of jobs when they landed in the US, from running a fishery to working on container ships, cooking Italian cuisine and building skyscrapers.

"Call me crazy, but I really miss New York's beat. I used to go around the whole time on weekends, take the trains, go to the movies with my friends, to restaurants, to the hairdresser, and just walk, walk walk. I still dream of that city energy," says Avellino. On Ponza, she says, there are no hairdressers in winter.

Despite her age and growing health issues, she says she'd love to go back to experiencing the thrill of the frenetic, pro-active New York City lifestyle that allowed her to meet many people.

"NYC gave me the chance to have so many experiences and job opportunities. It was an exciting life," says Avellino.

"I miss everything of the Big Apple: the workaholics, the traffic and the constant noise. The buzz of the steel factory and the supermarket's quick beat, where I also worked. I was always on the run. Ponza is beautiful, the panorama is stunning but there's nobody here."

During summer, the island's population rises to over 20,000 people, with hordes of beachgoers cramming Ponza's paradise-like beaches. But in winter there are barely 1,000 residents in Le Forna district, where Avellino and Romano live. It is the most offbeat neighborhood, far from the touristy spots, where Ponza's oldest families still live.

Culture clashes

Ponza natives live off farming and fishing, but mainly seasonal tourism. The island comes to life from June to October, with the remainder of the year being quite "dead and sleepy," as Romano calls it.

Avellino, who says she feels more American than Ponzese, says that she's happy she got an American education and passport, which she keeps in her bedside closet.

In fact, she says, it was a blow for her when she eventually had to return to Ponza after her father had a heart attack. On Ponza, she met her future husband, Silverio -- a native Ponzese -- and gave birth to Loredana, who kept ties with relatives back in the US.

She went back and forth between the US and Ponza between the ages of 20 and 30, working as a waitress at one of her aunt's restaurants in Florida. Today, she's now proud to be living in the cave home which her great-grandfather dug from the cliff with his own bare hands.

She's now on a mission to recover her ancestral origins.

"I inherited this cave, which I recently lavishly restyled. My great-grandpa built it just before leaving for the US for work. He wasn't really an economic migrant, nor was he poor, he just wanted to change life and look for new opportunities on the other side of the Atlantic," says Romano.

The 860-square-foot cave dwelling is located in Ponza's most scenic spot, overlooking two natural sea pools sheltered by white granite cliffs. It has direct access to the tropical-like waters.

The living room features an old well used in the past as a cistern to collect rainwater, which Romano still exploits when there's little running water during summer.

This year, she redid the cave's façade, and planted a small garden and vegetable plot of eggplants and zucchini, with which she makes local recipes.

Unlike her mother, Romano -- who works in Ponza's tourism sector -- doesn't feel nostalgic of the US lifestyle.

"In Florida I lived in the Italian neighborhood. Americans are extremely kind -- they always say hello -- but when you live in a metropolis with tons of people and you don't know many, you really find yourself alone and more isolated than on an island," she says.

Americans, in her view, live only to work. They don't have time to go to the grocery to buy fresh food or to spend quality time with friends and relatives. They don't cook but prefer to eat out, she says.

Ponza, on the other hand, is a small island which makes Romano feel safer. Neighbors watch out for one another, and partake in sorrows and joys.

"Here, when there is good news, like a wedding or birth, the entire neighborhood parties, we're a big family. When there's a funeral, we're all sad."