Frank Sandoval (front row, far right), an engineer in the U.S. Army during World War II, was killed while building -- and defending -- the Ledo Road in the China-Burma-India Theater. He was one of 57 children from 22 Mexican immigrant families that had settled on Second Street in Silvis, Ill. who had fought in World War II or Korea. [Photo courtesy Tanilo H. Sandoval and Georgia Herrera]

The families of what is now known as Hero Street were shunned. They were forced to live in railroad boxcars, without electricity or plumbing, on an unpaved street. Snow blew through the cracks in the walls in winter. The street turned to mud when it rained.

The kids who grew up there still remember the other school kids calling them “dirty Mexicans.” They remember being made fun of when their parents pulled them out of school to go top onions in the fields across the Mississippi, in Iowa. They remember the KKK crosses burning at the top of the hill above the street, the message clear.

Yet, when World War II came, the 22 families on that tiny, block-and-a-half long street went to fight, to defend the United States. In fact, between World War II and Korea, they sent more of their children to fight than any other place that size in the country — 57 in all. One family sent seven; another sent six. Eight died.

I wrote about them with all of that in mind. The book is called The Ghosts of Hero Street. Since it came out last month, I’ve been asked the same question time and again: Why? Why would people treated so miserably give so much for this country?

The answer is both simple and complex. That’s why I wanted to write the book. It was to me, a truly American story.

The families who wound up on Hero Street in Silvis, Ill., a couple of hours west of Chicago, came for the same reason everyone did, and still does.

They came looking for the American Dream. Opportunity. Liberty. Equality.

The first two are handed out at the door. The instant we get here, we have an opportunity that most of us would never have anything close to where we came from. In many places, our possibilities are determined at birth. A child born into poverty in much of Latin America is almost certain to see his own child born into the same a generation later.

America, however, beacons with a promise heard round the world. We come already knowing stories of Chaplin and Houdini, of Bell and Einstein, Marcus Goldman and the Lehman Brothers. And we know the dream still happens. We see it in the stories of PayPal, Tesla and SpaceX founder Elon Musk, of Sergey Brin of Google. Heck, we gobbled popcorn (palomitas or rositas where I come from) watching a muscle-bound immigrant with a mouthful of a name and an unshakeable accent, Arnold Schwarzenegger, become an American hero and a multimillionaire married into the equivalent of this country’s royalty, and, later, (talk about the American Dream!) the governor of California.

Where in the world can that happen but here?!

Here, people have opportunity, and the liberty to pursue it. They have the liberty to pretty much worship as they please, and to pretty much say what they believe without getting locked up or thrown out.

So people risk their lives on rafts in the shark-infested Florida Straits to come here from Cuba; or, similarly, risk death among the snakes and coyotes – human and wild – crossing the parched deserts of the American Southwest.

They come here willing to work hard, often at jobs nobody else really wants. Stooped to pick tomatoes all day under the hot Florida sun for a whopping 96-cents for each 32-pound bucketful. Digging ditches as off-the-books day-labor or toiling in the squalid stench and ankle-deep excrement of a poultry or pig processing factory.

Or to fill jobs on railroads in the cold near the banks of the Mississippi, even if it meant living in a cast-off train car and scavenging for lumps of coal that fell off the passing engines to use for heat and cooking. That’s how those Mexican arrivals lived in Silvis in the early ‘40s.

And they knew, just like the Irish and Italians who had come before them to labor in sweatshops and crowd together in tenements, just like the Chinese who came to swing picks and lay the tracks of the first railroads in the West – just like every immigrant who has come, willing to do whatever they could and whatever they had to – all of those jobs are opportunities. They are a chance to build a better life for themselves and for their children, and a chance to put down roots.

So, when the country comes calling, they step up. Because this country is where their children will have opportunities and liberty, too. And that’s worth fighting for. It’s a big part of why the forefathers fought to create this country in the first place, and why we celebrate Independence Day.

But, like any dream, the American one also includes an element of fantasy. That equality part. That’s not so easy.

It’s not just today. In this country, historically, new immigrant groups are treated as lesser human beings. Need proof? Think for a moment. Our national lexicon is full of disparaging terms for people of every race, every ethnicity and every nationality ever to set foot here: Germans, Italians, Poles, Irish, Asians, Hispanics. You name ‘em.

Historically, equality exists in how we equally mistreat newcomers.

And that’s where it gets complex. Because that’s another reason people who come here and are treated so shabbily give so much for this country.

They want to show that they are a part of this country, even if they’re not treated like it. They want to show they love this country, even if it doesn’t love them back. They want to show that they came to give, not to take.

They embrace this country long before it embraces them.

Just like everyone else.

Carlos Harrison is a Pulitzer Prize-winning journalist and the author of The Ghosts of Hero Street. He will be reading from and signing his book at the National Museum of Mexican Art in Chicago, Wednesday, June 25 at 6 p.m.