IF ONLY tHE wIFE COULD TOLERATE TWO HOURS OF SUNLIGHT...:

Every Icelandic town, no matter how small, has its own pool. There are ramshackle cement rectangles squatting under rain clouds in the sheep-strewn boonies. There are fancy aquatic complexes with multilevel hot tubs and awesomely dangerous water slides of the sort that litigious American culture would never allow. All told, there are more than 120 public pools -- usually geothermally heated, mostly outdoors, open all year long -- in Iceland, a country with a population just slightly larger than that of Lexington, Ky. "If you don't have a swimming pool, it seems you may as well not even be a town," the mayor of Reykjavik, Dagur Eggertsson, told me. I interviewed him, of course, as we relaxed together in a downtown hot tub.

These public pools, or sundlaugs, serve as the communal heart of Iceland, sacred places whose affordability and ubiquity are viewed as a kind of civil right. Families and teenagers and older people lounge and chat in sundlaugs every day, summer or winter. Despite Iceland's cruel climate, its remoteness and its winters of 19 hours of darkness per day, the people there are among the most contented in the world. The more local swimming pools I visited, the more convinced I became that Icelanders' remarkable satisfaction is tied inextricably to the experience of escaping the fierce, freezing air and sinking into warm water among their countrymen. The pools are more than a humble municipal investment, more than just a civic perquisite that emerged from an accident of Iceland's volcanic geology. They seem to be, in fact, a key to Icelandic well-­being.

This past winter, I visited Iceland and swam in 14 pools all over the country. I found them full of Icelanders eager to discuss what role these underwater village greens played in their lives. I met recent immigrants to the Westfjords town Bolungarvik as they mingled with their new neighbors, their toddler carrying fresh handfuls of snow into the hot tub and delightedly watching them melt. I saw Icelandic parents splash with their kids to calm them before bedtime; I talked to adults who remembered that ritual from childhood and could summon the memory of slipping their still-warm bodies between cool sheets. I heard stories of divorcing couples splitting their local pools along with their possessions and retired couples bonding by swimming together every day. I watched four steaming septuagenarians swim laps in a northern Iceland pool while the sunrise lit up the mountains behind them and an attendant brought out foam cups of coffee balanced on a kickboard. "I think the swimming pools are what make it possible to live here," the young artist Ragnheidur Harpa Leifsdottir said. "You have storms, you have darkness, but the swimming pool is a place for you to find yourself again."

For centuries, Iceland was a nation of seamen who regularly drowned within sight of shore. One local newspaper reported in 1887 that more than 100 Icelanders had drowned that winter alone. In 1931, a boat carrying four farmers capsized while they tried to row a panicking cow across Kollafjordur fjord. Three of the men died; one, who had studied swimming, survived.

Incidents like this fostered an enthusiasm for swimming education. At the time, the only place to learn was a muddy ditch downstream from the hot spring where the women of Reykjavik did laundry. Inspired by that hot spring, and using a heavily mortgaged drill that had been brought to Iceland to search fruitlessly for gold, the city soon tapped the underground hot water generated by Iceland's volcanic underbelly. Iceland's first geothermal heat flowed into 70 homes and three civic buildings: a school, a hospital and a swimming pool. The national energy authority offered no-risk loans to villages across the country to encourage geothermal drilling, and within a generation, the ancient turf house had nearly disappeared from Iceland, replaced by modern apartment buildings and homes, all of them so toasty warm that even on winter nights most Icelanders leave a window open. With hot water flowing through the country and a populace eager to take a dip -- swimming education was made mandatory in all Icelandic schools in 1943 -- pools soon popped up in every town.

"Because of the weather, we don't have proper plazas in the Italian or French style," the writer Magnus Sveinn Helgason explained to me. "Beer was banned in Iceland until 1989, so we don't have the pub tradition of England or Ireland." The pool is Iceland's social space: where families meet neighbors, where newcomers first receive welcome, where rivals can't avoid one another. It can be hard for reserved Icelanders, who "don't typically talk to their neighbors in the store or in the street," to forge connections, Mayor Dagur told me. (Icelanders generally use patronymic and matronymic last names and refer to everyone, even the mayor, by first name.) "In the hot tub, you must interact," Mayor Dagur continued. "There's nothing else to do."

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