Tracy Peguero was shoeless and searching for her other boot.

It was an odd place to lose a boot, of course, standing there in the middle of a public park in the Bronx, surrounded by thousands of strangers. But the boots had about a two-inch heel on them, and Peguero, a 17-year-old student at Mott Haven Village Prep, didn't want them to get in the way of all the jumping up and down and dancing she and her classmates planned to do that night.

For Peguero, this night was a rare opportunity to see a presidential candidate—in this case, Democratic candidate Bernie Sanders—up close, just blocks away from their high school, and some silly heels weren’t going to stop her from joining in what was, for many Bronx natives, a once-in-a-lifetime opportunity.

As Peguero’s history teacher Melissa Cohen put it, “No one ever comes to the South Bronx.”

It wasn’t the first time I heard that sentiment on Thursday night as 18,500 Sanders supporters gathered in St. Mary's Park, waiting for him to take the stage. “Things like this don’t happen in the Bronx, and I was born and raised here,” said Pablo Muriel, another teacher from nearby Alfred E. Smith High School, who brought several dozen students out to the event.

“He’s making us visible again,” said Dhalimu Robinson, a South Bronx small business owner with an "I Heart Bernie" pin affixed to his lapel. "He’s here during the primary season. He's not just saying I’ll get to them later, and then forgetting about us like every other candidate usually does."

It's true. While primary season may seem long to the rest of us, it's still not long enough for candidates to touch every corner of the United States. So, they tend to visit the places where they believe they'll have the most impact—that is, areas with high voter turnout rates or big communities of wealthy donors.

From left to right: Steven Reyes, Pablo Muriel, Malik Webb, Kenny Flores Issie Lapowsky

In places that have neither, like the South Bronx, they've been relying on Facebook, Twitter, YouTube and other digital channels to communicate with voters. In many ways, these platforms have been revelatory, giving candidates the ability to campaign everywhere by delivering targeted messages to hard-to-reach voters.

But while social media may give candidates the ability to campaign everywhere in the country from anywhere in the country, Sanders' event in the Bronx this week proves that in an often overlooked neighborhood like the South Bronx, there's no digital substitute to just showing up.

"No other candidate has come to the Bronx to express himself," said Kenny Flores, 17, one of Muriel's students. "That’s what it’s about, coming to the Bronx and showing you want to change the world."

According to Muriel, Sanders' visit was the talk of the neighborhood in the days leading up to the event, and outside the park, it's obvious the area is energized. That afternoon, as a line of people snaked around the park, a group of enterprising grade schoolers stood outside PS 277 soliciting donations for Flint, Michigan on the sidewalk. Later, the corner pizza joint was filled to capacity with Sanders supporters grabbing a last minute slice, and an employee from one local gym handed out flyers, saying, "You feel the Bern? Then feel the burn."

As he leaned against a signpost, taking in the neighborhood's sudden transformation, I heard one onlooker shout, "Yo! Bernie's bringing em in! Bernie's doing his thing!"

The South Bronx is, in many ways, the encapsulation of Sanders' stump speech. Just 10 miles away from Wall Street, the Vermont senator's favorite target, more than 40 percent of people live in poverty in the neighborhood of Mott Haven, where the event was held. Just weeks ago, a 20-year old man was murdered in a gang fight in this very park.

By kicking off his New York City campaign here, Sanders made Clinton's 1,500 person event at Harlem's Apollo theater, where everyone from Ella Fitzgerald and Louis Armstrong to Aretha Franklin and Michael Jackson has performed, look predictable by comparison.

"This is one of the areas of the Bronx where you can see the disparities of income inequality," said Erika Andiola, Sanders' national Latino press secretary, who delivered a riveting opening address about her experience as an undocumented immigrant in the United States. "You can really see the reality of our country here."

And yet, Sanders' central obstacle to winning the New York primary on April 19 will be cutting through the name recognition that former New York Senator Clinton has in this and other predominantly minority neighborhoods in New York. A recent Quinnipiac poll found that 66 percent of black Democrats in New York back Clinton, versus 31 percent for Sanders.

In his opening speech Thursday night, Sanders supporter and director Spike Lee admitted as much, saying, "We have to talk to our parents, because the older generation, they on this Clinton thing."

Sure, the Sanders campaign can (and does) spread the word about the senator on social media, but the people of the Bronx could just as easily tune it out. A nearly 19,000 person block party smack in the middle of the Bronx was pretty hard to miss. What's more, it only fueled the already impressive social media operation the Sanders campaign has built, as thousands of Facebook posts and Tweets shared from the event made the hashtag #BernieIntheBronx start trending.

Estefania Marmolejos, 16, is one of the 1.1 million people who follow Sanders on Instagram. And while she said it's been cool to follow the campaign online, in the park she was literally wiggling with excitement, her smile so wide it looked like it probably hurt. "It’s crazy. I come here every single day, and it’s just like, a political figure? Here?" she said. "It’s amazing!"

Excitement like that is ubiquitous at Sanders events. In fact, one reason why live rallies are so critical to Sanders, in particular, is because of the nature of the campaign he is running. Sanders is fond of saying his campaign is "Not about me. It's about you," and anyone who's ever been to one of his events knows that much is true. Whether it's at a rally in Iowa City or in the South Bronx, Sanders' crowds tend to be as excited by each other as they are by the candidate himself.

By now, they know what Sanders will say. He rarely strays from message. But it's the energy of the audience that feels raw and new each time—the kind of energy that makes you want to toss off your shoes in the middle of a public park and jump around.

Try getting that reaction from Twitter.