In more than two decades of reporting in Havana, I’ve grown accustomed to the visual signatures of the city: grimy old buildings, rattletrap cars, little that is new or bright. But that is only on the surface; in Cuba, there is always an inside, a life of interior spaces, and this is especially true amid the city’s hidden gems of architecture.

Teatro América is one such gem, concealed in plain sight behind a dull screen of gray polygon concrete on Galiano Street. When the theater opened, this part of Centro was the commercial artery of Havana, and the marble walkways held the names of now vanished department stores. Galiano is still chaotic—during my visit in March, I was nearly flattened by a man unloading smoked ham hocks from the trunk of a 1950s car, and had to push aside mattress vendors to reach the theater. But step inside and you are in the museum that is Cuban architecture.

There is no city in the world so layered with hidden beauty. Yet today, as Havana opens to the world, it is also poised at the edge of collapse. Love of the city, which I have visited regularly for a quarter century, brought me back looking for answers: Can a place long known for its decay become dedicated to preservation? What can be done to protect its architectural legacy? And how can that be accomplished while also meeting the growing demands of Cuba’s hard-pressed and ambitious people?

Havana is a city easy to navigate, limited by the sea and divided from its suburbs by a river. Each neighborhood seems defined by historic landmarks. Old Havana, founded in 1519, still spreads out from the original Plaza de Armas, the civic space of medieval Spain. Next out from the harbor, in distance and time, is its modern equivalent, the Parque Central district, overseen by the National Capitol building, based on the Panthéon in Paris (not the U.S. Capitol, as sometimes claimed). Next are the elegant and faded apartment blocks of fin-del-siglo Centro, followed by the Vedado business district, still dominated by Welton Becket’s 1958 Hilton hotel, a 25-floor modernist statement renamed the Hotel Habana Libre. Beyond, there is the 20th-century suburb of Playa, visually defined by the spacious and arrow-straight Avenida Quinta (“fifth avenue”), lined with the luxurious mansions of Cuba’s old rich and miles of precise topiary.

Even symbols of communist power—the tower of what was once the Soviet Embassy in Miramar, or the barren asphalt plain of Revolutionary Square—have redeeming value in making orientation easy.

Then all you have to do is look up. “Havana is a library of architecture,” says Raúl Rodríguez, a Cuban architect-in-exile with a deep passion for Cuban history and architecture. “Every style is well represented there, and the reason for its magic is the tripartite culture”—African, American, European.

From the very beginning, the city was a mixture: star-shaped forts from medieval Europe, shaded Moorish colonnades, Greco-Roman columns, French landscaping, and the iconic Malecón seawall built by the U.S. Army Corps of Engineers. Exiled Bauhaus stars like Walter Gropius visited Cuba during the 1940s, and with an influx of influential Cuban architects trained at Columbia University, the city became an eclectic crossroads.