I’m standing at the top of Colonia del Sacramento’s “Street of Sighs,” an 18th century passageway built by the Portuguese when they still controlled this peninsula in present-day Uruguay. The original trough running down the center of the mossy-stoned lane continues to drain rainwater to the Rio de la Plata lapping just yards away. Two rows of aged ocher, rose and russet stucco buildings now serve as art galleries and artisanal cheese stores. I’m captivated by a scene of beauty created by cobblestones, wrought-iron lamps, coastal bluffs and, of course, prostitutes.

My tour guide, Maria del Carmen, has just informed me that the galleries and gourmet shops on this street were brothels in a former lifetime, beckoning the many seamen who washed up on Colonia’s shores. One of several legends explaining how Colonia’s most photogenic street got its name claims that the sailors would sigh over the women of easy virtue as they walked down the road.

I’ve taken the hour-long ferry ride from chaotic Buenos Aires to this enchanting colonial city across the river in search of tranquility. Thanks to the prostitutes, I’ve found it. According to Maria, the prostitutes are responsible for Colonia’s preservation of a bygone era. The ladies of the night held court on this street and the surrounding alleyways until a mere 40 years ago. Along with other impoverished souls, they kept the Barrio Historico the precinct of ne’er-do-wells while the better-off chose to erect new edifices farther inland.

Thus were the historic buildings saved from the demolition and modernization that has condemned many other would-be tourist magnets to the dustbins of history. Once the tourism industry recognized the perfectly preserved district’s appeal and took over — culminating in a UNESCO World Heritage Site designation in 1995 — skyrocketing rents forced the prostitutes out.

That’s just one historical irony in a place now prized for its tranquil beaches and relaxed atmosphere but originally a military fort whose early decades were steeped in blood and turmoil. Although the Portuguese chose the location as a strategic port from which to challenge the Spanish and then spent decades duking it out with their archenemy, Colonia is now synonymous with peace and quiet.

MAKING AN ESCAPE

After two weeks studying Spanish in Buenos Aires, enduring a daily diet of crazy drivers, diesel-cloaked air and trash-covered streets, I was ready for a place where pollution is a foreign word and cars actually stop for me when I cross the street. Sometimes when I’m not even in a crosswalk. Tourists, for their part, almost never bother with cars here, preferring to rent glorified golf carts because an automobile would move them too far too fast.

And this is not a place for moving quickly. For one thing, there’s not a lot here. It’s possible to walk from one end of the old town to the other in less than 15 minutes, so there’s no need to rush.

Each year thousands of tourists make the mistake of thinking that because you can take an easy day trip to Colonia from Buenos Aires via a one-hour high-speed ferry, that’s what you should do. Sure, in one day I could scale the 118 tightly wound steps of the lighthouse for a panoramic view, cross over the reconstructed colonial drawbridge to roam along the old city walls, and squeeze in a picnic on the reedy beach.