Getting Exposed to the Good Life in Sultry Rio : The naked truth is residents of the world’s 10th-largest city shun conventional rules.

You walk into a bank to cash a check on a normal, and seasonably steamy, December workday. At the counter window, you are greeted by a teller dressed in a Rio de Janeiro “business suit.” That is, she is wearing shorts cut from a gray tweed-like cloth that barely reaches the top of her thigh, and a broad-lapel jacket buttoned at the waist with no blouse, only an extensively revealed and revealing black lace bra.

If you are new to Rio, you must be careful not to show any surprise at the scantiness of this business apparel. The only ogler in the bank line will be you.

Observers of Rio’s illustrious annual carnival cannot fail to note the tendency of Cariocas, as Rio residents are called, to gravitate toward nakedness. But Carioca informality goes beyond the pleasure of displaying corporeal endowments. Although Rio, with its population of 11.4 million, is the world’s 10th-largest city, bigger than any American metropolis except New York, its residents are peculiarly reluctant to adopt conventional rules of civilization. Rio is a city in form, but not in spirit.

Perhaps this is the result of its setting. Much of Rio is squeezed in among rocky hills so precipitous that no one can live on top of them. On the south it is bound by surf-battered beaches, and from its heart rises Tijuca National Park, more than 8,000 acres of tenebrous tropical forest a few minutes from downtown. From nearly every vantage point, there is some visual reminder that the state of nature is not far away.

Just behind the skyscraper at Rio Sul, a sleek office building and shopping mall that is a monument to Rio’s modernity, wild goats graze on a steep slope. In addition to cockroaches and other universal urban vermin, Rio is inhabited by an impressive variety of snakes, which can turn up twisting languorously around the planted palms at apartment building entrances.

Urban mores never prevail completely. In Ipanema, the swank beach-side neighborhood, the sidewalks of the frenetic business district are shared by crisp executives with ties and briefcases and barefoot surfers clad only in the barest swimming briefs.

After the summer rains end in April, the hills above Rio are engulfed in the tall flora that flourish in the moist heat. To control the overgrowth, city workers often resort to that approach to landscape management that gained Brazilians global notoriety: they burn. There’s no reason to be alarmed when an entire hilltop above a crowded residential community becomes a crackling torch, illuminating the evening sky. It’s only the municipal gardeners doing a bit of weeding.

One Carioca pastime is building and flying unmanned hot-air balloons. These paper aircraft stand the height of a human and are lifted by kerosene-fueled flames in their bases. Launched at night on certain saints’ days, they carry tails of fireworks that are rigged to start popping once the balloons are airborne. They sail high into the heavens and drift like resplendent orange UFOs.

Yet this is less than ideal entertainment for a teeming city. As the rule dictates, these balloons, too, must come down. Not a few residents have had their St. John the Baptist festivities brought to an unpleasant end by an uninvited fireball that came plunging through the living room window.

Though countless Cariocas require cars to get around and are renowned for their homicidal driving, they resist institutionalizing the dominion of the automobile in their lives. For example, they don’t like to put road signs on major highways. City streets, even obscure cul-de-sacs and narrow alleys of the sort where the denizens all know each other, are carefully identified with ceramic plaques and heroic titles. But on the main artery out of Rio, to mention only one case, the only turnoff onto the expressway to Sao Paulo is not marked. Those who don’t know where Sao Paulo, Brazil’s biggest city, is have to find it by the more traditional and sociable--albeit time-consuming--method of word of mouth.

Similarly, in the center of Rio sits the Maracana soccer stadium, said to be the world’s largest, with room for 200,000 spectators. But Maracana has no parking lot. Admittedly, when it was inaugurated in 1950, few of Rio’s largely proletarian soccer fans could afford cars. But since then many fans have acquired wheels, and every time there is an event in Maracana, they park in the surrounding avenues, knotting traffic in every direction for hours. No one seems to think it should be otherwise.

One local resident who personifies the Carioca disdain for conventionality is taxi driver J. Moura, better known as “The Kisser.” For the past decade, Moura has made it his business to try to sneak past the security guards of most of the major figures who have appeared in public in Brazil, in order to plant a long, loud kiss on the personality’s cheek. He began with Frank Sinatra in Maracana stadium in 1980. Soon after, he struck again with Pope John Paul II, but, out of respect, limited himself to kissing the pontiff’s feet.

Bishop Desmond Tutu and rock star Peter Gabriel have been kissed, along with many of Brazil’s prominent politicians. Most recently, The Kisser was arrested moving toward the generous jowl of Luciano Pavarotti. Baffling security contingents is a key part of Moura’s campaign. The more the burly bouncers try to impede his displays of affection, the greater the triumph of a successful smack. In writing about Moura, the Folha de Sao Paulo newspaper noted that, consistent with the Carioca style, in Brazil, the serial killer has become a serial kisser.