Not long ago, my wife put up a black-and-white photograph in our living room. It shows her grandparents, very young — supposedly on a street in Ciudad Juarez, Mexico.
This summer, on a whim, I pulled that picture out of its frame and had a closer look.
I quickly realized they weren't in Ciudad Juarez at all. And with just a little detective work, I entered a world that is lost to history now, when two cities were joined together as one, despite the narrow river and the international border between them.
To show my wife and kids exactly what I learned, I decided to take them all on a 2,000-mile road trip to El Paso.
"I don't want to go to Texas," one of my sons said. But I'm a dad, and my word is law, so I dragged him and his brother and sister east anyway, despite advice that summer is not a good time to visit El Paso.
I'm a firm believer in the idea that you can learn a lot by standing at a place where history unfolded, whether it's the history of your family, your country or your ancestors. I've taken my kids to the U.S. Capitol, the pyramids of Teotihuacan in Mexico and the campus in Northern California where my wife and I first met.
To me, taking them to Texas was just as important. I wanted them to understand that when their great-grandparents passed through those border towns, they were a place of hope.
Divided by the slow-moving Rio Grande, the twin cities of El Paso and Juarez are a continental crossroads. Thousands of L.A. families have roots there.
This is also the place where my kids' maternal great-grandparents first met, started a family and eventually crossed over from Mexico.
Luis Alberto Chavira died in 1995. His widow Guadalupe is 97 now and isn't up to being interviewed. But some years back she told me how she met Luis on the bridge over the international border. It was a wintry day when the Rio Grande beneath them flooded and they were stranded in the middle.
The photograph in question was snapped some years later, in 1933. Luis is wearing the cap of his then employer, the Mexican postal service and seems to have a bounce in his step. Guadalupe is wearing a nice winter coat and high-heel shoes that suggest she's out for a day on the town.
After scanning and enlarging the picture, I noticed English words in the background: "Bus Stop" and "Five Entire Floors." On a hunch, I turned to Google Maps to pinpoint the location.
After 30 minutes of scanning the present-day cityscape with Google's "street view," I found the location — at the corner of Mesa Street and Texas Avenue in El Paso.
Luis had apparently picked up Guadalupe at the end of his workday at the Mexican post office and taken her to the U.S. on a late-afternoon visit. It was a reminder of the ease with which people crossed the border in those days.
"It was really a casual back-and-forth across the river then," said Pat Worthington, curator at the El Paso County Historical Society. A trolley route connected the two cities.
In the first half of the 20th century, downtown El Paso was a lively, elegant destination, Worthington said. It was there, in 1929, that Conrad Hilton opened his first high-rise hotel.
The tall structure in the left of the photograph is the Caples Building. Francisco I. Madero, the politician who helped launch the Mexican Revolution, established his headquarters as an exile there in 1911.
The storefront right next to the couple housed the Elite Confectionery, famous in El Paso as the place where another revolutionary, Pancho Villa, stopped for copious servings of peanut brittle and strawberry soda during his own brief exile in the U.S.
When my family finally reached El Paso after a two-day drive, we found all the old buildings in the photograph.
It was very odd, I thought, to be standing on a block in Texas that had hosted so many episodes of Mexican history. But Mexican and U.S. history are woven together in many ways in El Paso.
El Paso was linked to L.A. by the Southern Pacific railway in the 1880s. To a good chunk of Latino L.A., El Paso and its bridges served as a kind of Ellis Island.
Luis and Guadalupe Chavira got their permanent U.S. residency there in 1945 and began a life in the U.S. now stretching into its fourth generation.
"I never wanted to come here because I thought of it as a place you move away from," my wife said after we visited the site of the photograph. "Now I see it has this rich history."
Digging deeper into public documents available online, I found border passes for the Chavira family issued by the U.S. immigration authorities in the 1930s. One listed a home address in Juarez that was just four blocks from the Rio Grande.
I had envisioned as the climax of our drive to El Paso a short walk across the border to show my family that home. "You can see where your grandmother was born," I told my kids.
But in El Paso, everyone I met told me to stay away from Juarez.
The drug wars are strangling life on the other side. During our Texas visit, the local news was filled with reports of Juarez atrocities, both random and calculated.
So instead of making the crossing, we drove to the top of an El Paso hill and looked down into Juarez's narrow streets.
The neighborhoods that hosted the Mexican chapters of our family story were, at least for the moment, unreachable. We could see them but not touch them. And that too was a kind of lesson about our history.
Today, more than ever, the cities in our Latin American past and the cities of our U.S. present are separated by powerful barriers.
But it wasn't always that way.
Once, a young Mexican postman of limited means could take his girlfriend on a trolley across the border for a strawberry soda. Or he could walk to the El Paso train station with his wife and begin an American family, entering a country where no one yet thought of building walls to keep people out.