The Iowa State Fair is a sight to behold.

There are carnival rides, concerts and colossal farm animals. There's a cow carved entirely out of butter. And you can get pretty much any food you want on a stick.

But what makes this event truly special is the politics.

The fair has become an almost-mandatory stop for presidential candidates looking to gain an edge ahead of the Iowa caucuses. And the informal setting gives voters a chance to see the candidates in a different light.

Photographer Mark Peterson has been on the campaign trail for months. He's in Des Moines shooting pictures of this year's fair, which started on Thursday and ends on August 18.

US Sen. Bernie Sanders and his wife, Jane, walk through the fairgrounds on Saturday. Most of the Democratic field visited the fair over the weekend.
US Sen. Bernie Sanders and his wife, Jane, walk through the fairgrounds on Saturday. Most of the Democratic field visited the fair over the weekend.
Mark Peterson/Redux for CNN
A fairgoer casts a vote at the kernel voting station.
A fairgoer casts a vote at the kernel voting station.
Mark Peterson/Redux for CNN
It wasn't just Democratic candidates attending the fair this year. Bill Weld, a former Massachusetts governor who is challenging President Trump for the Republican nomination, talks to the media on Sunday.
It wasn't just Democratic candidates attending the fair this year. Bill Weld, a former Massachusetts governor who is challenging President Trump for the Republican nomination, talks to the media on Sunday.
Mark Peterson/Redux for CNN
Dark clouds loom over the Ferris wheel on Sunday.
Dark clouds loom over the Ferris wheel on Sunday.
Mark Peterson/Redux for CNN
Fairgoers take shelter under an umbrella during a rainy Sunday.
Fairgoers take shelter under an umbrella during a rainy Sunday.
Mark Peterson/Redux for CNN
A young man poses with cutouts of President Trump and first lady Melania Trump.
A young man poses with cutouts of President Trump and first lady Melania Trump.
Mark Peterson/Redux for CNN
US Sen. Kamala Harris speaks to fairgoers on Saturday. The Des Moines Register gives each candidate a soapbox, a microphone and 20 minutes to address fair attendees.
US Sen. Kamala Harris speaks to fairgoers on Saturday. The Des Moines Register gives each candidate a soapbox, a microphone and 20 minutes to address fair attendees.
Mark Peterson/Redux for CNN
More than 100,000 people attended the fair on Saturday.
More than 100,000 people attended the fair on Saturday.
Mark Peterson/Redux for CNN
US Sen. Elizabeth Warren meets with supporters after her speech on Saturday.
US Sen. Elizabeth Warren meets with supporters after her speech on Saturday.
Mark Peterson/Redux for CNN
A Cory Booker supporter sits in the crowd on Saturday.
A Cory Booker supporter sits in the crowd on Saturday.
Mark Peterson/Redux for CNN
The Iowa State Fair has approximately 500 concession stands and exhibitors.
The Iowa State Fair has approximately 500 concession stands and exhibitors.
Mark Peterson/Redux for CNN
Booker explores the fair on Saturday.
Booker explores the fair on Saturday.
Mark Peterson/Redux for CNN
Men take a rest for some food and lemonade on Saturday.
Men take a rest for some food and lemonade on Saturday.
Mark Peterson/Redux for CNN
Many fairgoers brought books for presidential candidates to sign.
Many fairgoers brought books for presidential candidates to sign.
Mark Peterson/Redux for CNN
People enjoy a large slide at the fair.
People enjoy a large slide at the fair.
Mark Peterson/Redux for CNN
A Slipknot fan shows off his tattoos before a concert at the fair on Saturday.
A Slipknot fan shows off his tattoos before a concert at the fair on Saturday.
Mark Peterson/Redux for CNN
A girl cools off with a snow cone.
A girl cools off with a snow cone.
Mark Peterson/Redux for CNN
A beauty pageant contestant bites her nails.
A beauty pageant contestant bites her nails.
Mark Peterson/Redux for CNN
Since 1911, the Iowa State Fair has had a cow sculpted out of butter. Each year, much of the butter is recycled. It can be reused for up to 10 years.
Since 1911, the Iowa State Fair has had a cow sculpted out of butter. Each year, much of the butter is recycled. It can be reused for up to 10 years.
Mark Peterson/Redux for CNN
Democratic presidential candidate Andrew Yang eats a corn dog at the fair on Friday. The corn dog is just one of 69 food items <a href="index.php?page=&url=https%3A%2F%2Fwww.iowastatefair.org%2Ffood%2Ffood-on-a-stick%2F" target="_blank" target="_blank">that you can find on a stick there.</a>
Democratic presidential candidate Andrew Yang eats a corn dog at the fair on Friday. The corn dog is just one of 69 food items that you can find on a stick there.
Mark Peterson/Redux for CNN
The first Iowa State Fair was held in 1854. It moved to its current address in Des Moines in 1886.
The first Iowa State Fair was held in 1854. It moved to its current address in Des Moines in 1886.
Mark Peterson/Redux for CNN
A contestant gets ready for the Iowa Cowgirl Queen Contest. According to the state fair's website, the contestants are judged partly by their Western attire and partly on their horsemanship.
A contestant gets ready for the Iowa Cowgirl Queen Contest. According to the state fair's website, the contestants are judged partly by their Western attire and partly on their horsemanship.
Mark Peterson/Redux for CNN
Presidential candidate Julián Castro, a former mayor of San Antonio who was secretary of Housing and Urban Development in the Obama administration, talks to fairgoers on Friday.
Presidential candidate Julián Castro, a former mayor of San Antonio who was secretary of Housing and Urban Development in the Obama administration, talks to fairgoers on Friday.
Mark Peterson/Redux for CNN
A particularly patriotic fairgoer.
A particularly patriotic fairgoer.
Mark Peterson/Redux for CNN
A young woman cleans the dairy barn -- an unglamorous but important job.
A young woman cleans the dairy barn -- an unglamorous but important job.
Mark Peterson/Redux for CNN
Former US Rep. John Delaney, a Democratic presidential candidate, was making his third visit to the fair on Friday.
Former US Rep. John Delaney, a Democratic presidential candidate, was making his third visit to the fair on Friday.
Mark Peterson/Redux for CNN
People hold their hands over their hearts as "God Bless America" is played before the Cowgirl Queen Contest.
People hold their hands over their hearts as "God Bless America" is played before the Cowgirl Queen Contest.
Mark Peterson/Redux for CNN
The fair has dozens of carnival games and rides, and there are plenty of toys, too.
The fair has dozens of carnival games and rides, and there are plenty of toys, too.
Mark Peterson/Redux for CNN
A young woman has her hair done for the Cowgirl Queen Contest.
A young woman has her hair done for the Cowgirl Queen Contest.
Mark Peterson/Redux for CNN
Castro supporters watch him speak on the soapbox on Friday.
Castro supporters watch him speak on the soapbox on Friday.
Mark Peterson/Redux for CNN
A girl and her cow relax between shows.
A girl and her cow relax between shows.
Mark Peterson/Redux for CNN
Democratic presidential candidate Marianne Williamson addresses fairgoers on Friday.
Democratic presidential candidate Marianne Williamson addresses fairgoers on Friday.
Mark Peterson/Redux for CNN
US Rep. Tulsi Gabbard, a Democratic presidential candidate, orders a veggie corn dog on Friday.
US Rep. Tulsi Gabbard, a Democratic presidential candidate, orders a veggie corn dog on Friday.
Mark Peterson/Redux for CNN
Women pose with their drinks at a photo booth.
Women pose with their drinks at a photo booth.
Mark Peterson/Redux for CNN
An average of 1.3 million people attend the Iowa State Fair annually.
An average of 1.3 million people attend the Iowa State Fair annually.
Mark Peterson/Redux for CNN
A young woman rides a horse while carrying the US flag.
A young woman rides a horse while carrying the US flag.
Mark Peterson/Redux for CNN