Old Havana, the historic district of Cuba’s capital, was founded by Spanish colonists in 1519. Its churches and fortresses carved from white limestone, Triangle Trade–era mansions, and airy courtyards tell a story of centuries of wealth and its expression by Cuba’s military and mercantile elite. But the district lost prominence in the early 20th century as economic growth shifted away from the city center, and by the time of the Cuban Revolution in the 1950s—when the country started to shut out foreign visitors, who once packed its bars and beaches—it had fallen into disrepair.

Today, Old Havana is the site of one of the world’s most ambitious urban-revival projects. The force behind this transformation is Eusebio Leal Spengler, the city’s chief historian. In the early 1990s, when the collapse of the Soviet Union pitched Cuba into economic crisis, Leal persuaded President Fidel Castro to approve the establishment of a tourist-management company, called Habaguanex, that would bring foreign investment back to the island. Since then, Leal’s office claims to have steered more than half a billion dollars to the historic district and created more than 13,000 jobs. Habaguanex controls some 20 hotels, 40 restaurants, and 50 bars and cafés, as well as dozens of stores that include a French pastry shop, a florist, and a United Colors of Benetton. Thousands of tourists now arrive each day in Old Havana, an area covering less than a square mile, making it the nation’s most popular destination for foreigners.

It has been a spectacular turnaround—but also an unsettling one. Although Castro said he wanted to restore the tourism industry as a “gold mine through which the country can obtain foreign exchange,” he regarded its cultural and financial influence on Cubans themselves with extreme caution. Until 2008, when Castro ceded power to his younger brother, the government forbade Cubans to stay in tourist hotels, including the grand Habaguanex lodges in Old Havana—part of a policy that Castro’s critics called tourism apartheid.

Leal sees nothing subversive about filling the streets with foreign visitors. To the contrary, he has described his project as the next chapter in the Cuban Revolution. Part of every dollar tourists spend at shops and restaurants pays to restore buildings that host museums, libraries, schools, and clinics; new hotels for foreigners fund new housing for locals. Leal’s approach to restoration—capitalist tactics for socialist results—has been resoundingly praised by the international architecture community.

But it has also heightened the contrast between squalor and splendor, creating a stark division in a land of supposed equals. Two-thirds of Old Havana remains unrestored, and blocks away from the new restaurants and souvenir shops, residents still live in tenements that threaten to collapse around them. Others have been displaced from their homes as the renovation has progressed. Opportunities for corruption abound. The thaw in U.S.-Cuba relations, expected to release big flows of tourists and capital, will likely accelerate the area’s changes. Will more outside money help Leal preserve Old Havana’s character—or hasten its decline?

At the turn of the millennium, only one in three housing units in Old Havana was in good condition; in the early Aughts, a partial or complete building collapse was recorded every day. Today, tourists throng the district's cafés and boutiques. (Photo by Lisette Poole)
A tour-bus driver smokes outside El Floridita, the bar where Ernest Hemingway drank daiquiris in the 1930s. The nearby Ambos Mundos Hotel, where Hemingway started writing For Whom the Bell Tolls, was one of Eusebio Leal Spengler’s first renovation projects after Habaguanex was founded. (Photo by Lisette Poole)
Since the 1990s, as hotels and restaurants have surrounded Old Havana’s ancient plazas, the Office of the Historian has restored hundreds of residential buildings in the historic district and funded new primary schools, maternity wards, and other public projects. (Photo by Lisette Poole)
An Habaguanex perfume shop on Obispo Street. A central tenet of Leal’s project is to avoid turning Old Havana into an urban museum, like Venice and other tourist-dominated European sites. (Photo by Lisette Poole)
The lobby bar of the Hotel Saratoga, which hosted Beyoncé and Jay Z in 2013. (Photo by Lisette Poole)
A new restaurant by the waterfront accepts only convertible pesos—a currency designed for foreign visitors and investors—which are much more valuable than the pesos the Cuban government issues its citizens. (Photo by Lisette Poole)
The interior of El Floridita (Photo by Lisette Poole)
The apartment building at 360 San Ignacio once housed more than 40 families. After being renovated by Leal’s office a few years ago, it now houses 15 families and, on the ground floor, a Lacoste store. (Photo by Lisette Poole)
The historic district has a population density higher than that of Manhattan, and many buildings remain dangerously overcrowded and run-down. “Habana Vieja is like a woman in rouge,” one resident told me. “Very pretty on the outside, and destroyed on the inside.” (Photo by Lisette Poole)
Javier Terry Camejo and Yasser Gorrita are neighbors in a multi-family apartment building—known as a solar—in Old Havana.* (Photo by Lisette Poole)
A man crawls through smashed shutters into an apartment just a few blocks from the Hotel Saratoga, which he reached by scaling the roof of the building next door. In June, the fourth-floor stairway collapsed. This window is now the only way that the dozens of fourth-floor residents can reach their apartments. (Photo by Lisette Poole)
Some Habaneros are reluctant to relocate from their crumbling homes as Leal’s project moves forward—especially now that they anticipate a boom in American visitors. “Right now, everyone is trying to create a business related to tourists,” Daniel de la Regata, an architect who worked for several years in Leal’s office. “They’d rather have money in their pocket than a good place to live.” (Photo by Lisette Poole)

* This caption originally misidentified the individuals and location shown in the photograph. We regret the error.