Second of three parts.

If you want to find the soccer player who is most likely to lead the U.S. national team to World Cup greatness, you probably won't see him on the squad that is currently trying to get to next year's tournament in Russia.

Indeed, you probably won't see him anywhere in Major League Soccer right now.

But you might see him in a one-story white building in an anonymous-looking office park in Wayne, a short drive down Route 202 from the King of Prussia Mall.

You'll have to look hard. The only major sign you're in the right place is across the small street between the office complex and the YSC Sports soccer facility.

When you get there, you'll be in the middle of one of the most-watched science experiments in American soccer: a full-time soccer high school run by the Philadelphia Union.

The Union and YSC owner Richie Graham, a part-owner of the team, have spent millions of dollars on the facility in an effort to develop the next generation of U.S. national team stars.

Launched in 2013, the school has 73 students from grades 8 through 12, and not just from the Philadelphia region. Many students come from other cities, and a few even come from other countries. They train twice a day and go to class for the rest of the time, and the out-of-towners live in residency.

It's the kind of setup you'll find at soccer clubs all around the world. It has rarely been done in America.

But becoming a true soccer power requires a development infrastructure as strong and deep as the world's elite. That's why these days, playing high school soccer and getting a college scholarship aren't enough. Now the best players turn pro at 18 and sometimes younger.

JESSICA GRIFFIN / Staff Photographer
Union academy coach Iain Munro (center) talks with players on one of the indoor fields at YSC Sports.

"All of us who are involved recognize the importance of developing the domestic player," Graham said. "The aspiration is to develop world-class players. . . . From our standpoint, there's no sense to set the bar at a lower standard."

He puts a particular emphasis on the culture created by the full-time high school environment. It's great to have all the latest equipment and technology, but the school helps build the mental edge necessary to thrive on the global stage.

"It is the center of the bull's-eye," he said. "A lot of times, when people think about elite development, they think about the passing drills. They think about the athletic development. They think about the fitness and all those pieces that come together. But they forget about the importance of culture and values."

The Union academy's work is starting to get noticed not just locally but nationally.

Midfielder Derrick Jones, 19, and defender Auston Trusty, 18, joined the Union's senior team last year and are fixtures on the U.S. under-20 national team. Both are likely to play in the FIFA under-20 World Cup in May if the U.S. successfully qualifies later this month.

Another defender, 17-year-old Matthew Real, signed a contract with the Union's minor league team, Bethlehem Steel, last month. He could be joined later this year by 16-year-old attacking midfielder Anthony Fontana, who impressed the Union's brass in preseason training sessions with the senior squad.

Any of those players, and others coming after them, could end up on the senior national team in the years to come.

U.S. Soccer Federation youth technical director Tab Ramos is among the increasing number of observers who are impressed by what the Union are doing.

"Their setup is amazing," said Ramos, who also coaches the U.S. under-20 team. "They're doing a great job, from the school to the way they develop to the way they train. They're one of the clubs that's an example to the other clubs as far as youth development and their model in general."

There is one way, though, in which the Union's approach is not so well-regarded. Annual tuition at the team's high school is $28,500, the kind of big check one would write for an elite private school.

But the price tag is mitigated by a significant amount of financial aid, totaling $1.7 million of the $2.1 million in tuition revenue on the budget. Graham said that's a big enough scholarship fund to ensure that if a child is a good enough soccer player, he'll get into the school regardless of means.

If a prospect wants to play for the Union's academy without going to the high school, that's possible too. The club runs official teams for age groups all the way down to under-12, and it doesn't cost anything to play for those teams.

JESSICA GRIFFIN / Staff Photographer
Students Axel Picazo (left) and Benjamin Ofeimu prepare for classes at the Philadelphia Union's full-time high school in Wayne.

While Graham works to knock down financial barriers at the local level, Ramos works at it on a national level. There might not be a bigger single issue in American youth soccer today.

The "traditional" American player pool has long been criticized for being too white, too wealthy and too suburban. The cost of playing soccer - equipment, club enrollment fees and frequent travel to major tournaments - is a major reason why.

So is a history of under-scouting the nation's melting pot of soccer cultures. In recent years, that tide has finally turned, but the work is never done. Ramos knows the national team pool must reflect the nation's growing Hispanic population, and an African-American population that's playing the sport in ever greater numbers.

That means spending more money to hire more scouts and send them to more places, especially outside of major population centers and traditional soccer hotbeds.

And by the way, those players are just as likely to speak Spanish at home as they are English. That point resonates strongly for Ramos. He was born in Uruguay, moved to northern New Jersey at age 11 and from there grew into one of the greatest American soccer players of all time.

"The Latino community has a lot to give," he said. "A lot of kids grow up at home with soccer being part of their culture. We at U.S. Soccer would like to be part of that, and I think we need to do better, and we need to do more."

Graham has heard that call loud and clear. According to statistics provided by the Union, 54 percent of the high school's student body identifies as a racial or ethnic minority. And while Philadelphia's Hispanic population may not be as big as those in Los Angeles or Dallas, the demographic is growing.

This region also has some unique assets, such as the African immigrant population in West Philadelphia. That's where Union scouts discovered Derrick Jones during a game against one of their youth teams. It didn't take long to offer him the opportunity of a lifetime: a path to a pro soccer career.

"I've had a lot of people come and visit the academy and the school, and some of the non-soccer people have always commented, 'Wow, it's super-diverse.' And I've said, 'Well, that's one of the beautiful things about the game of soccer,' " Graham said. "We have a full-time talent identification scout who then has a system of part-time scouts. We have folks that are connected into some of these communities that give us an opportunity to understand what's happening."

Each time the Union's scouts find a player to bring in, they take another step toward helping the United States finally win a men's World Cup. There's still a long way to go until the puzzle is solved, but Graham is confident that it will happen.

"We're American, so we want our McDonald's in five minutes," he said. "Some things you actually can't build in five minutes or get in five minutes. We have to roll up our sleeves and do the work. . . . That's what we're trying to do at the local level, and that fits into the national story."

If Graham and the Union do their jobs right, that national story will have a significant chapter written by authors from Philadelphia.