Before Opening Day, I took a walk around the Nationals Park neighborhood. After a decade of what looked like slow progress, it seemed that the whole area — a genuinely vast 60-square-block chunk of Southeast Washington — had changed far more than I had imagined.

I came back stunned. Washington has won. And it has won big.

The development project began more than a dozen years ago as an extremely ambitious dream by the D.C. government to transform a blighted section of the city into a riverfront showpiece. That grand plan has now flown past critical mass. There’s no stopping it.

[Wilson Ramos’s late home run lifts Nats to 1-0 win over Mets]

The concept of revitalizing a desolate portion of Southeast predated the arrival of the Nats from Montreal. But the controversial ballpark, which cost D.C. taxpayers $670 million, was always envisioned as a prime economic engine. It worked, with the Nats a key part of the synergy.

1 of 52 Full Screen Autoplay Close Skip Ad × 2016 Nationals: Trea Turner jacks a walk-off homer to center field View Photos Rookie continues to make a name for himself. Caption He’ll be the Game 1 starter Friday against the Dodgers. Nationals 10, Marlins 7 On the final day of the regular season, Max Scherzer won his 20th game. Afterward, he hugged his catcher, Pedro Severino. Toni L. Sandys/The Washington Post Buy Photo Wait 1 second to continue.

Economically, aesthetically and in quality of city life, the transformation of Southeast, which moved at a crawl during the Great Recession and often slipped from the public consciousness, has fulfilled and in some ways surpassed expectations. In fact, I’m probably a couple of years late to the party.

But unless you live within walking or bicycling distance of Nationals Park, even if you go to Nationals games, there’s an excellent chance that, like me, most of the success story is still a mystery to you.

Within an 11-minute walk of the home plate entrance to Nationals Park, I jotted down the names of 13 restaurants, in all price ranges, including one of the best in the city. I meandered down the mile-long Riverwalk beside the Anacostia River. When Nationals Park was built, my preconception was that, no matter how well the overall project went, you could never get near the Anacostia without holding your nose.

In reality, after hundreds of millions of dollars spent by D.C. Water on its clean rivers project, the walk by the Anacostia is pretty, panoramic, breezy and odorless. And it’s lovely at sundown. I looked for something ugly — anything. I spotted a floating stick. The wide, wooden Riverwalk is broader than the concourses in Nationals Park. It’s so spacious you don’t even notice passing bicyclists.

Seven minutes from Nationals Park you come to The Yards, an enormous park with children and families playing in the grass beside a large shallow reflecting pool in which kids are allowed to splash. Modern sculptures frame the view of waterfront restaurants. New, handsome apartment buildings — not the office buildings that were originally expected — set the neighborhood’s tone. Originally, the idea in Southeast had something to do with Make Money. It still does. But “I want to live here” showed up, too.

I’ve taken side trips to explore the area from South Capitol Street to the Navy Yard at 11th Street, and from the Anacostia to roughly four blocks north of M Street. My wife and I took friends, who are such fans that they have Nats-themed license plates, down the Riverwalk to The Yards — a 10-minute walk from Nationals Park in total. “We had no idea this was here,” they said.

Ironically, Nationals Park was designed to be near the Navy Yard Metro stop to discourage the need for cars and parking, while funneling thousands of fans down Half Street to the entrances beyond left field. If you judged by nondescript, semi-developed Half Street, you’d think that time stopped when the park opened in 2008. Where’s the grace, the sense of place, the nice eateries and bars — everything that was promised? Before the All-Star Game arrives in D.C. in 22 months, Half Street will probably have come to life. Or be close. But don’t be fooled (as I was) and stick to the narrowest path. Explore.

No one has chronicled the transformation of Southeast like blogger Jacqueline Dupree (JDLand.com), who also works at The Washington Post. Anything you want to learn, or any photo — before and after — that you might want to see from more than a dozen years is there. We’ve talked occasionally, probably with the cynical undertone of people who are wary of hoping that too much can go right in a big, bureaucratic city. “What will go wrong? What will spoil it?” we’ve asked. She has monitored every delay and zoning hearing, every setback to construction.

So this week I asked her, because she also lives on Capitol Hill, “What am I missing? It can’t have worked out this well.” She said, “It’s just ridiculous . . . but in a good way.”

Perhaps the biggest surprise is that because of the dead years for construction in 2009 and 2o10, the financing for office buildings and even condos was harsh. So the emphasis, even in property owned by the Lerner family, who own the Nationals, switched to residential.

There’s still new office and retail, and more to come. D.C. always hoped that the density of its Southeast development would be extremely high — perhaps denser than some residents will like in a few years.

But the urbanists and D.C. politicians like Tommy Wells, who talked about “The Livable Walkable Community,” have seen their vision come to life. The new Southeast isn’t about cars. And when the new D.C. United soccer stadium (with a capacity expected to be around 20,000) is built on the other side of South Capitol Street in Southwest Washington, expanding this whole project area to roughly 80 square blocks, the style and tone will remain consistent — pedestrian and cyclist friendly, welcoming to anybody, 10 or 80, who likes to walk 20 minutes.

Who may howl? Perhaps suburbanites who find traffic difficult and parking expensive if they want to get close to the park. But, to be blunt, the District government structured the funding of Nationals Park so that, in part, it would serve as a commuter tax — taking a slice of tax revenue from every ticket sold or hot dog bought — more than 80 percent of which are bought by Virginia and Maryland residents who are Nats fans.

The city wanted a building and population boom in what had been a bleak area of town; part of the benefit would be seen in property taxes and sales taxes. But the prime beneficiaries of this were always intended to be Washingtonians themselves, like those seen pouring down from Capitol Hill in a wave of red before Nats games.

This column avoids civic-mindedness — no doubt a character flaw. But rules have exceptions: You ought to go to Nationals Park for a game before the season ends, or forget the baseball and just walk the neighborhood while the weather is beautiful, so that you can see the “middle” stage of a before-and-after transformation that someone (me) who grew up 20 blocks from Nationals Park can barely believe.