Hillary Clinton on the campaign trail

CLEVELAND, OH - On the third day of a bus tour through Pennsylvania and Ohio, Democratic Nominee for President of the United States former Secretary of State Hillary Clinton along with running mate Senator Tim Kaine, and Anne Holton, aboard the campaign bus in Cleveland, Ohio on Sunday July 31, 2016. (Melina Mara/The Washington Post)

This story has been updated.

DES MOINES -- All of the forces that have unexpectedly made this presidential contest epically memorable, and often entertaining, collided at the Iowa State Fair on Saturday.

Donald Trump, the television personality turned GOP presidential contender, in what may be a state fair first, arrived in a helicopter. And just in case that isn't enough to impress Iowans, the colorful billionaire is allowing local children to go up for a free ride while he checks out the fair's famed cow carved out of butter.

Hillary Rodham Clinton, the Democratic front-runner, also made an appearance at the fair on Saturday, with an entourage of security, staffers and a swarm of reporters shouting questions. And rounding out the presidential hopefuls roster on Saturday is U.S. Sen. Bernie Sanders of Vermont, who is also running for the Democratic nominee and has been quickly climbing in early polls and attracting massive crowds at rallies.

The Iowa State Fair is already a bit of a spectacle itself, as summed up in this slogan: "Nothing compares." More than a million people attend each year to inspect hundreds of farm animals, listen to live music, ride the Ferris wheel, play games on the midway, have a couple beers or eat several days worth of calories in one meal. The food is a hallmark of the state fair, and this year there are nearly 200 booths competing to take fried delicacies -- especially fried food on a stick, with bonus points for the inclusion of bacon -- to new culinary heights. Menus include deep-fried nacho balls, bacon-wrapped smokies on a stick, deep-fried Twinkies, a double-bacon corn dog, pumpkin-spice funnel cake and something ominously called an "Ultimate Bacon Brisket Bomb." (Note to readers: It's okay to feel like you need an antacid after just reading that sentence.)

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On Saturday, the Democratic and Republican front-runners made the pilgrimage to Des Moines.

Jerry Lynch lucked into the best possible shift volunteering to man the Gammon Barn at the Iowa State Fair. For most of his 8 a.m. to noon shift, he could stand on the porch outside, watching the press mill around waiting for the arrival of Hillary Clinton. With Secret Service at the entrance ramp to the barn, there wasn't much else to do.

Lynch breeds Hereford cows at a farm in eastern Iowa and is a retired middle school guidance counselor. He's not a stranger to state politics, though; he serves on the central committee in Dubuque County. But he hadn't made up his mind who to support yet, first because it's "damn early" and second because the Democratic National Committee asked him to participate in a group trying to figure out how to bolster turnout for the caucus. (Perhaps thanks to so many other Democrats having already made up their minds about who to support.)

After a few minutes, the unexpected: someone less interested in politics and more interested in his barn arrived. "Hey," Lynch exclaimed,"someone wants to see the Hereford barn!"

Clinton arrived at the fair just after 11 a.m., accompanied by former U.S. Sen. Tom Harkin, who just endorsed her. Clinton shook hands with a few of the fairgoers who waited in the sun for an hour to see her, and then stepped back to wave at the others. Before addressing a swarm of reporters, she and Harkin stopped to chat with a young boy watching the spectacle with his white and brown calf.

"I'm deeply honored to have Tom's support," Clinton told the dozens of reporters who gathered for a rare opportunity to ask her questions."

As Clinton arrived to talk to the press, former Iowa Sen. Tom Harkin steered her to a nearby paddock where Nolin Lang was waiting with his milking shorthorn Maggie.

Wayne hadn't meant to meet Clinton. He just wanted to sneak Maggie into some photos. So when Harkin asked "would you like to meet the next president of United States?," Lang didn't respond. Clinton chimed in. "Well we're going to meet you."

Lang was asked if that result was better than getting his cow in some pictures. "It was a lot better," he said.

A couple dozen Iowan children and their parents gathered at a baseball field near the state fair grounds and excitedly waited for the arrival of Donald Trump and his helicopter. The campaign had been promised to take as many of them as possible up for rides to see the state fair from the air.

"They said there's enough fuel for an hour," said Niccole Rose, 33, who is on the board of directors for the ballfield, which is how her three kids -- ages 15,12 and 8 -- were invited, although they are in the fourth group and warned there might not be enough gas and time to take them up.

A few parents admitted that they aren't too politically involved and haven't been closely following the election -- but they proudly wore white T-shirts emblazoned with Trump's name and gushed about his straightforward style.

There were also a few super fans who stealthily tracked down the helicopter's precise landing spot. Two women brought along a blanket decorated with Trump's face and slogan.

One of those fans: Joe McNeley, 54, who said he used to be a Democrat but hasn't voted in a presidential election in years. McNeley said he loves Trump, and wants to see him become president.

"Since the Bush years, I haven't been interested in putting anyone in power," said McNeley, who lives in Ankeny, just outside of Des Moines. "Mr. Trump -- he's not in the political realm. He speaks his mind and he's not afraid."

As the sound of helicopter blades became louder, the Iowan children who were randomly selected for this Willy-Wonka-like opportunity -- a chopper ride with a presidential candidate who they've likely only seen on TV -- ran out of the shade to watch his descent.

The helicopter lowered toward the parking lot next to a baseball field near the fair grounds, throwing up leaves and dirt at the swarm of waiting reporters. The door opened and out he came, sporting a red baseball cap with the message "Make America Great Again" and bright white shoes that likely wouldn't do well in the cow barn.

Trump made his way toward a fence separating him from a horde of reporters and declared: "It's a great honor to be here."

Then he looked around for his backdrop: "Where are the children? Get them over here. That's great."

When asked by a reporter why he had staged this spectacle, Trump said: "I love children. I love Iowa, great place. I've really developed a relationship with it. And it's an amazing place."

Trump turned back to the young fans behind him, many wearing campaign shirts they had received that day. Some were the children of friends of campaign staffers, others the kids of the ballfield's board of directors.

"I love my kids," Trump said. "Come here. Does anyone want to take a ride? It's nice, right? ... Who wants to go first? We're going to have some fun... They're going to have a great time. It's a great experience."

Trump then took questions from reporters -- often devolving into his usual rants about the loss of jobs to other countries, the need to be fiercely protective of the U.S., the greatness of the wall he will build on the southern border and the need to, as his hat says, make America great again.

If he ran into Clinton at the fair, what would he say? "I would say hello."

As a reporter tried to ask Trump about comments he'd made yesterday about rival GOP presidential candidate Jeb Bush, Trump cut him off from finishing the question and let everyone know, at length, what he thought about Bush "Jeb Bush is a puppet to his donors, there's no question about that. And he's got lobbyists. I know them... And, you know, he made statements over the last couple of days that are incredible, trying to justify the war in Iraq -- I can't be justified."

He called Bush's "skin in the game" comment "one of the dumbest things I've ever heard" and likely an attempt by Bush to protect his brother "because I understand psychology."

As Trump's comments continued, hitting 15 minutes and continuing on, the children behind him became restless. The mogul stopped taking questions, posed for a photo with all of the children and then started loading people onto the helicopter: "It's a beautiful machine, isn't it?"

The helicopter ride was brief, just a few minutes in the air and a quick circle of the fairgrounds. Trump left his chopper at the ball field so other kids could get a turn. He hopped into a gold cart and headed to the fair.

Iowa's status as home to the first-in-the-nation presidential nominating contest has made its the state fair a rite of passage for those who dream of becoming the next president. But it's also a political obstacle course that has tripped up many prior candidates. In that laid-back atmosphere -- and with a stomach roiling from consuming who-knows-what -- it's easy to get too casual, too flippant, too funny, too trusting of reporters with cameras. With time have come these lessons: Don't wear a suit. Don't order the corn dog -- and if you do, don't jam it straight into your mouth. Don't cut the line to see the butter cow. Don't get grease stains all over your shirt. And don't say things like: "Corporations are people."

For Clinton, the fair was also a test of her retail-politics skills, another chance to push back at the image critics and rivals have painted of an impersonal and aloof politician who is unable to connect with voters. Her campaign has largely focused on placing her in settings with small groups of voters, although she did attend a Fourth of July parade in New Hampshire last month -- only to have her appearance overshadowed by hecklers and outrage over her staffers using a rope to keep reporters away from the candidate.

Several other candidates have already made their requisite pilgrimage to the state fair this year. Bush strayed from his strict Paleo diet on Friday, eating a pork chop and deep-fried Snickers bar (both on a stick, of course) and downing a beer well before lunchtime. Former Arkansas governor Mike Huckabee (R) and his wife sampled some pork on Thursday morning. That afternoon, former Democratic senator from Virginia Jim Webb schmoozed with a George Washington doppelganger and former Maryland governor Martin O'Malley (D) posed for selfies in front of the butter cow.

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As fair-goers mobbed Clinton and Trump, Sen. Bernie Sanders (I-Vt.) -- whose campaign said he'd had to switch a Sunday rally in Dubuque, Iowa to a larger venue -- made his way to the the Des Moines Register Soapbox.

"I'm no communist!" Steve from Cedar Rapids yelled when he saw Sanders pass by. "I'm no communist!"

Asked to explain his comment, Steve (who wouldn't offer a last name) said that Sanders was "a scary person."

"He's like Dr. Jekyll and Mr. Hyde," Steve said. "Once he gets into office, he's going to change."

Near where Sanders was meeting people, another argument broke out. Keith Hora was arguing against socialism, despite being on Medicare, which he referred to as "socialized medicine."

He didn't agree with Steve, though. "There's a difference between communism and socialism," he said.

As Sanders's voice boomed from the tiny soapbox stage with his call for "political revolution," a swarm of onlookers stopped in their tracks to listen, making the main-course of the fair nearly impossible to cross for roughly 15 minutes. For those trying to get through so they could exit the fair -- or buy a root beer float, super-sized corn dog or Dutch letter at stands just beyond the soapbox -- there were occasionally screams of "Move!"

As he spoke, Sanders, one of the race's least wealthy candidates, spotted Trump's helicopter hovering above. "I apologize -- we left the helicopter at home. I forgot to bring it," he said.

Trump and Clinton had already opted out of appearing at the soapbox, a beloved state fair tradition: an opportunity for presidential hopefuls to share their vision for the future of the nation with fair-goers -- and get mercilessly heckled. The risk is high. After all, the soapbox is where former Republican presidential nominee Mitt Romney in 2011 made the "corporations are people" comment, a damaging gaffe that followed him to the election. Former Florida governor Jeb Bush (R) took the soapbox challenge as he visited the fair on Friday and was endlessly pelted with questions about the legacy of the two former presidents in his family and the Iraq war.

Clinton drew pre-visit criticism for not partaking in the tradition. Trump -- who is often more than eager to answer questions -- said he was skipping the soapbox because of an ongoing feud with the Register: "I don't do that because that paper was, in my opinion, not relevant," he told reporters Saturday.

Philip Rucker contributed to this report.