From her teeming, shadowy streets to her sunny plazas, Havana is charming, proud and shabby, like a high-priced courtesan at the end of her career. With few exceptions, her façade is crumbling, dingy and decrepit. Beneath more than 40 years of neglect, though, her bones are still impressive. And those few exceptions are simply magnificent. During a recent visit, Sarasota architect Eugene Aubry and I could easily see the rich beauty that was Havana, and with a squinting of the eye and a tilt of the head, the comeliness that one day-we hope-will be again.

Nowhere is this more true than in Vieja Havana, the old quarter of Cuba's capital city. If architecture is about light and space, form and function, people and their lifestyle, then Vieja Havana serves as an architectural manual, not only about the last 500 years of Cuba's history, but about the ideal urban environment for Florida.

The old quarter forms a rough semicircle to the west of Havana Harbor, separated by a narrow neck of sea from the eastern heights dominated by the Castillo de Tres Reyes del Morro and the Fortaleza de San Carlos de la Cabana. Havana's original construction plans included fortifications to protect its inhabitants and the riches plundered by Spain from the Americas on their way back to the old country. Only a few of the most massive of those fortifications remain. They are impressive in their design, construction and simple decoration.

Most of the city's beauty lies in the structures of the 18th century, which dominate the old quarter, and the residences, shops, fabricas and warehouses along her narrow streets, where a three-foot sidewalk lines the cobbled roadway and adjoining structures melt seamlessly into each other. Behind wooden doorways are fabulous old homes, now packed with multiple families in response to an economy of equality and scarcity.

Old Havana's basic design model drew heavily from Colonial Spain, modified for the harsh New World environment. The style, which Addison Mizner and others made famous in Florida in the early part of the last century, is variously known as Spanish, Neocolonial or Mediterranean Revival. Thick, decorated exterior walls reflect the heat and retain the cool of night; and windows open onto balconies, allowing light to penetrate and accelerating the rush of cooling breeze from courtyard to street. Interior courtyards once were filled with greenery and, perhaps, tinkling fountains. Arcades along calzadas, or main thoroughfares, protected walkers from sun and tropical downpours alike, while shoppers perused wares at ground-floor stores. Most shopkeepers lived in apartments above.

The old city's plan is one of compact blocks, each divided into long, narrow lots. There is unity in general appearance, with common building materials and techniques predominating, as well as similar ceiling, balcony and decorative unit heights. Most buildings are relatively low, usually three or four floors.

Occasional plazas open the vista and usually focus on an ancient church, palace or governmental building. Fringed by The Malecon, Havana's sea-splashed, grand Gulf-front promenade, the terrain slopes gently from a central height to the harbor.

Vieja Havana is a heat island, with an average temperature more than three degrees hotter than the rest of the city because of its high density, flat, reflective rooftops and scarcity of green space. Yet it's much cooler inside the buildings than it would be in taller, detached buildings subject to the merciless pounding of the sun. It is a design that makes sense in the tropics, particularly in an environment without air conditioning.

Ironically, the very economic conditions that left Old Havana a shadow of her former glory are those that saved her. This wonderful architecture has not been destroyed with fast-food establishments as in Milan and Venice-though not necessarily for want of trying. During the late Batista years in 1958, a plan masterminded by the Soviets would have raised the exterior walls up a few meters and created covered walkways like those found along the many plazas throughout the city. The plan also called for building an artificial island covered with high-rises along the waterfront directly in front of the Malecon.

Luckily for lovers of preservation, that proposal was never implemented, perhaps because Fidel Castro intervened.

Today Cuban architects and the government are united in their desire to preserve their architectural legacy, but they face a critical lack of funds for their restoration and urban planning efforts.

Architect Amaury Tosco Telleria, principal specialist of the office directing the physical plan of Havana, and his boss, Segundo Medina, discussed the challenges to Havana's infrastructure during a meeting at the Hotel Nacional on The Malecon in Havana. The city's biggest challenges, they agreed, are moving people through Havana and providing them with clean, clear water for residential, industrial and agricultural use. But it could be a long time before Tosco and Medina implement the government's 10-year old plan, to meet those challenges.

"There's no money," explains Medina.

And that's the key to Cuba. There's no money. The cash economy runs in dollars. Literally. Buy lunch, a magazine, an airline ticket, and you'll do it with U.S. dollars. British, Italians and French tourists all change their pounds, lire and francs into dollar bills. But it is illegal for U.S. citizens to spend dollars in Cuba, with a few exceptions requiring special licenses such as for journalists.

Until there is a change in government-or at least a change in relationship with the United States-there's not likely to be any real development money, either.

We met Conde Caribe's president Christina Baumann Massie at the Nacional, too. She held court at a table in the sixth floor's executive suites, speaking to her guests about construction and development in English, Spanish and German each morning of our visit.

How will she make money? "If we build a hotel, say, in Havana, with German financing, we can expect to receive U.S. dollars in return, unless we strike a deal for some kind of barter arrangement."

Just what kind of barter arrangement remains to be seen. Cuban exports are-at best-weak. There's only so much sugar, rum and cigars the rest of the world will buy.

Tourism, most of it from Europe and Canada, serves as the major source of ready capital. Funding provided by tourism is being diverted from preserving the architecture, which travelers come to Havana to see, to food, medicine and clothing, which makes sense in a desperate economy. Housing needs are met in the most rudimentary fashion.

In the Miramar district just west of downtown Havana where many former and current embassies are located, you can often find a three-story, 100-year-old townhouse with one family per bedroom and another over the garage, all sharing common spaces such as the kitchen and bath. In formerly commercial buildings in Vieja Havana, you're likely to spot a young mother hanging hand-wash over the balcony. If she is lucky or knows an official, she and her family might get what was once a corner office.

There are signs of redevelopment downtown, but progress is painfully slow. Only the worst cases of deterioration and collapse are being addressed. Many buildings are eviscerated, leaving only the skin intact. Untouched structures, which include nearly all of the built inventory in Vieja Havana and along the Malecon, show beautiful bones, but are in desperate need of plastic surgery. In Florida, most of them would be put to sleep.

Nearly all the new development is taking place in the suburbs, says Tosco. Much of what we saw appears to be instant tenement. "We're spreading the city to the south and east," he says. "Of course, then we need to find ways to get our people to work."

Public transportation is a joke. Most people walk or ride bikes to work. Private automobiles are virtually unknown. In Cuba, nearly every truck carries people. Rare is the pickup carrying produce, the dump truck hauling construction mate´riel or the stake-bed toting tires.

Certainly, Castro has done some good things, most obviously in education and medicine. People appear to be healthy. (We saw no fat Cubans.) And the literacy rate is among the highest in the world.

"But we're like a tiny man with a big head," says Tosco. "We have the brains and the education to be strong; but in reality, we have no ability to do anything."

Meanwhile, many tourists come to Havana primarily to see the legendary architecture of Vieja Havana, so evocative of the mystery and intrigue, the light and shadow of this beautiful city. If the world is not to lose this treasure, something must be done. Something must change-and change quickly.