Bernie Sanders hits the 2020 campaign trail with rockstar status, a far cry from the start of the 2016 campaign

Sanders' first rally in Iowa on Thursday was in Council Bluffs, not far from the Nebraska border.

As attendees waited for the senator to take the stage, a band kept them entertained.

People of all ages attended the rally — college students, senior citizens, and families with children.

Dan Griffith, 36, a volunteer at the rally from Prairie Home, Nebraska, was particularly excited to be there. Griffith told INSIDER he supports Sanders because he's been "saying the same thing for the past 30 years and he's right" on issues like climate change and raising the minimum wage. He also said President Donald Trump's policies are "total bullsh--t, we're better than this."

The room was fairly sleepy until Sanders took the stage, and then the crowd exploded as he asked, "Are you ready for a political revolution?"

Sanders began by referring to Trump as "the most dangerous president in modern American history."

"Donald Trump wants to divide us up by the color of our skin, our country of origin, our gender, our religion and our sexual orientation," Sanders said. "We are going to do exactly the opposite."

When the crowd chanted his name, Sanders interrupted and shouted, "Not me, you!" This is linked to his 2020 campaign slogan: "Not me. Us."

At one point in the rally, Sanders was interrupted by a man in the crowd as he began to say, "Tonight, we say to Donald Trump and the fossil fuel industry..." The man shouted, "F--k you!" This prompted laughter. Sanders paused and said, “Well, that is one way of phrasing it. I, myself, was gonna say it a little differently. I am a senator.”

The man who yelled, Terry Anderson, 53, of Omaha, Nebraska, told INSIDER his outburst was inspired by his belief that Trump is a "black stain on the face of the American society." Anderson, who also identified himself as "Tie-dye Terry," said he's a big Sanders supporter but is also a fan of other 2020 Democratic candidates like Rep. Tulsi Gabbard and Sen. Elizabeth Warren.

Sanders told the crowd that when he began his 2016 campaign, he was not well-known and his ideas were dismissed as "too radical." Just a few years later, Sanders claimed a majority of Americans now embrace his views and "shock of all shocks, those very same ideas are now supported not only by Democratic candidates for president but by Democratic candidates all across the board."

Sanders speech in Council Bluffs, which was similar to the subject addresses he delivered in other parts of Iowa, focused heavily on issues he spoke a great deal about in 2016: climate change, health care, and wealth inequality. But he also focused a lot on topics he was criticized for not addressing enough last time around: racism and racial justice.

"We are also going to address the racial disparities that exist. It is not right that white families have 10 times more wealth than black families ... We are going to end institutional racism wherever it exists," Sanders said to a mostly white crowd (in a predominantly white state). He got big cheers for this line.

Sanders ended his first Iowa rally with a message of unity: "If we stand together, this country has an extraordinary future. Let's make it happen."

Sanders second rally in Iowa was at the University of Iowa in Iowa City. Most of the attendees were college students who made their anti-Trump sentiments abundantly clear.

Freya Buhr, 19, of Clermont, Iowa, is such a big fan of Sanders she attended his rally on her birthday. Buhr told INSIDER she supports Sanders because he's "always been on the right side of history" and is a "feminist." She also thinks Sanders is a "strong leader" and "the kind of person we need with the current political discourse in America."

Sam Johnston, 18, of Forsyth, Illinois, told INSIDER he supports Sanders because he's "fair," "reliable," and he trusts the senator to "follow through" on his campaign promises. When asked if he's at all concerned by the fact Sanders is 77 and would be the oldest president in US history if elected, Johnston said "age range doesn't matter" because he "just knows our values and shares them."

Anthony Schulte, 19, of Cedar Rapids, Iowa, told INSIDER he supports Sanders because "nothing is more important to me than climate change." Schulte, who came to the rally with Johnston, added that it matters to him Sanders is "not in bed" with Wall Street and big corporations.

Aluna Olaniyi, 18, of Fairfield, Iowa, told INSIDER she supports Sanders because "the ideals he believes in I also believe in. She added, "[Sanders] has held the same values for a long time, so he's obviously not wishy-washy."

When Sanders took the stage and announced he's running the campaign that will "defeat Donald Trump," the crowd went wild.

Sanders went on to say that Trump "embarrasses" the US every day. The youthful crowd booed at the mention of Trump's name.

Sanders went after Trump hard in his speech, stating Trump doesn't really stand with "working people." He referred to the president as a "pathological liar" who "rejects science." Meanwhile, people wearing hats in support of Trump could be spotted in the crowd.

"I say to Donald Trump and the fossil fuel industry: climate change is not a hoax, but is an existential threat to our country and the planet," Sanders added. The crowd exploded.

Climate change was apparently such a big issue for Iowans that some attendees of Sanders' rallies wore shirts expressing their concern about it.

After Sanders wrapped up his speech in Iowa City, he walked off the stage and took selfies with attendees. Meanwhile, people in the crowd shouted,"We love you, Bernie."

Sanders' final Iowa rally was in Des Moines, the state capital. It was a rainy day but that didn't stop people from coming out. A Sanders campaign aide told INSIDER roughly 1,400 were in attendance.

Like Sanders' other rallies, the day started off with some live music as the crowd waited for the man of the hour to take the stage.

One of the first speakers at Sanders' third Iowa rally was Abshir Omar, a Somali Muslim refugee. Omar told the harrowing story of his mother's flight from conflict in his native country when he was a child. "Bernie Sanders makes me believe in the promise of America," Omar went on to say. "The same promise that got my mother to America.”

Sanders took the stage after another speaker. Early on his speech, he addressed a concern linked to his 2016 campaign: "If we do not win, I will strongly support the Democratic nominee and hope and believe that other people feel the same way. Donald Trump must be defeated!"

In his Des Moines speech, Sanders continued to touch on similar themes, and took a direct jab at Trump: "I don't come from a billionaire family. My parents didn't give me a $200,00 allowance when I was 3-years-old. My family knew what it was like to live paycheck to paycheck. I know where I come from, and I will never forget that!" Sanders had employed the same rhetoric at his 2020 kick off rally in Brooklyn, New York, a week earlier.

Sanders avoided getting personal in 2016, but he's started to touch more on his working class, Brooklyn roots in the early days of his 2020 campaign.

Sanders' speeches in Iowa were filled with the same firebrand, progressive rhetoric that typified his 2016 campaign, but with sharp criticism of Trump sprinkled in. At the Vermont senator's Des Moines rally, at least one or two of the president's red 'Make American Great Again' hats could be seen in the crowd.

As Sanders spoke in Des Moines, a dedicated crew of sign-wavers made their affinity for the senator quite clear.

Other attendees carried signs expressing their concern about climate change.

Sanders' Des Moines speech focused on issues impacting rural communities, including suicide rates and declining life expectancy. "If I’m elected president, we’re going to start paying attention to rural America," Sanders said.

Speaking on wealth inequality, the crowd in Des Moines went wild when Sanders said, "We have the people...They might have money and power, but there are a hell of a lot more of us than them."

After Sanders finished his speech, he went down to greet and speak with people in the crowd. The senator took selfies with and hugged some of the attendees.

Sanders three-day visit to Iowa showed that he is a top contender among the large field of candidates for the 2020 Democratic nomination. In roughly four years, the senator has gone from a relatively obscure member of Congress to one of the most influential political figures in the country.