Any Puerto Rican, it seems, will gladly discuss the pros and cons of the island's relationship with the United States. The forts San Felipe del Morro (El Morro) and San Cristóbal are run by the U.S. National Park Service, though it may seem odd to see that familiar ranger hat within a Spanish-colonial military castle. Suffice it to say that, try as they might, the friendly rangers fail to impress the locals, who regard them as something like turncoats. "Don't believe anything the Parks Department says!" an exasperated private tour guide tells us. "They don't know anything." The exhibits at both El Morro and San Cristóbal were heavily U.S.-centric, paying more attention to the guns of World War II (which never saw action) and to the Spanish-American War than to the first four hundred years of the fortresses' history and the town's struggles with pirates, buccaneers, sieges, and fires.

At the time American troops poured into the Old City, in the summer of 1898—there are photos of this early occupation in the San Juan Museum on Norzagaray—San Juan was known as one of the most attractive cities in Latin America, with stately public buildings, elegant homes from the seventeenth, eighteenth, and nineteenth centuries, and the only sewer system on the island. As the years passed, the Americans began hitting golf balls into the ocean from the field of fire at El Morro, which they renamed Fort Brooke. With two new red-light districts and tawdry bars to cater to the soldiers and with military trucks cruising the cobblestoned streets, many long-established San Juanero families packed up and moved away, as did the city's religious communities (the Franciscan brothers on Calle San Francisco, the Dominican sisters on Norzagaray, and the Carmelite nuns on Cristo), which relocated to Santurce, a neighborhood two miles away.

The wood-beamed, marble-tiled houses sat empty, crumbling in the sea air, as Puerto Rico endured a half century of economic and political malaise. The first sign of recovery came in the 1950s, when the U.S. Congress eased its grip and allowed Puerto Rico to write its own constitution. By 1960, the island had largely transformed itself from a rural society to an industrialized one. The U.S. military, having outgrown the limited quarters, left the Old City in 1961, just as dozens of Cuban businessmen fleeing Castro—fine jewelers mostly, but also owners of restaurants and bakeries—took up places on calles Fortaleza and San Francisco, finding Old San Juan a passable miniature version of Havana.

"It was very lucky that Puerto Ricans don't like to sell their houses," says Jan D'Esposo, an artist and the owner of the Gallery Inn, who moved into her pink house on Norzagaray in the early 1960s and subsequently bought six adjacent ones. "They left them alone, and they stayed fairly intact," she says. "There was something left to restore." Led by Ricardo Alegría, an outspoken university professor of history who fought to preserve the Old City's architectural character, Old San Juan reinvented itself. Alegría pushed owners to either sell or fix their properties. As incentive, a 1955 law, still in effect, abolished property taxes for those who maintain their buildings according to Institute of Culture standards—stone or tile floors, beamed ceilings, among other things, and an exterior paint color that is different from those of immediate neighbors. An abandoned hospital became a fine arts school; a convent became the Hotel El Convento, still the city's best (it had been scheduled for the wrecking ball in the 1950s, until Alegría convinced city officials that a parking lot might be better located elsewhere).