Uncle Joe is back, everyone! On April 25, the former vice president made his long-awaited announcement, declaring that yes, Biden is running for president. In a video posted to YouTube, Biden announced his intent to "fight for the soul of a nation," and referenced the deadly white supremacist rally in Charlottesville, Virginia in 2017.

"The core values of this nation, our standing in the world, our very democracy, everything that makes America America is at stake," Biden said in the video, over a montage of historic milestones in American history like the suffragist movement and Martin Luther King Jr. delivering a speech. "That’s why today I’m announcing my candidacy for President of the United States."

Biden's announcement came after months of speculation and early polls that showed him as a popular frontrunner, so it's not terribly unexpected. In 2016, Biden declined to run for the presidency following the emotional toll of his son Beau's death from brain cancer the year before. Four years on, he seems ready for the challenge.

O'Rourke may not have won his 2018 Texas Senate race, but he's got his eye back on the prize for 2020. On March 14, the former U.S. representative announced his bid for the presidency in a video posted to social media. "The challenges we face are the greatest in living memory," he wrote in a tweet. "No one person can meet them on their own. Only this country can do that, and only if we build a movement that includes all of us."

O'Rourke became a household name with his narrow loss to Ted Cruz in the 2018 Texas Senate race, an impressive showing for a Democrat in the solidly-red state. Whether he can translate that into a victory in 2020? We'll see.

John Hickenlooper, the former governor of Colorado who served from 2011 to 2019, officially entered the race on Monday, March 4. Hickenlooper, who was described by The New York Times as a "socially progressive, pro-business Democrat" — and who reportedly plans to run as a "pragmatic progressive" made his announcement in a video released on Monday.

"I'm running for president because we're facing a crisis that threatens everything we stand for," he said in the video. "I've stood up to my fair share of bullies."

Hickenlooper is known as a moderate with an ability to reach across the aisle, per CNN, and successfully worked with Republicans to expand Medicaid in Colorado and pass methane gas regulations. He'll hold his first campaign rally in Denver, Colorado, on March 7, per the Times.

On Friday, March 1, Washington Gov. Jay Inslee announced his candidacy, putting his name forward on a platform of combatting climate change. He introduced his bid with a video entitled "Our Moment," in which — as The New York Times pointed out — he said "climate" at least 10 times in the under a-minute-and-a-half video.

“This is our moment, our climate, our mission. Together, we can defeat climate change. That's why I'm running for president,” reads the caption on the video's YouTube page.

Inslee has served as governor of Washington since 2013, per the Times, where he has made climate issues a focus of his time in office. It's clearly something he intends to pursue. In January, he said in an interview with The Atlantic that if elected, he would focus on the effect of climate change on national security and the economy as well as the environment. “We have two existential threats right now: one is to our natural systems, and one is to our economic systems,” he told the publication.

Is America feeling the bern? On Feb. 19, the Vermont senator and one-time 2016 presidential candidate threw his hat back in the ring, announcing his candidacy with a video shared on Twitter. "I am asking you to join me today as part of an unprecedented and historic grassroots campaign that will begin with at least 1 million people from across the country," he wrote. Though he serves in Congress as an Independent, Sanders ran in 2016 as a Democrat, and appears to be seeking the party nomination again.

Clearly, a lot of people were down to join him. Within 12 hours, his campaign reported an astonishing $4 million in donated funds, most of it from small donations. That's quite a start, and one to beat.

Speaking to a crowd of supporters from a snowy stage in Minnesota on Sunday, Feb. 10, Sen. Amy Klobuchar (D-Minnesota) announced her 2020 presidential campaign. Her speech focused on quite a few areas of concern, including voting rights, the effects of climate change, and reforming campaign finance laws, per CNN. Speaking to that, Klobuchar told the crowd, "There are insidious forces every day that are trying to make it harder for people to vote, trying to drown out our voices with big money."

She closed with what sounds like it will be a recurring message during her campaign:

It’s time to organize. Time to galvanize. Time to take back our democracy. It’s time, America!

The Minnesota senator also spoke about her desire to fight for comprehensive immigration reform and universal health care before putting out the call for voters to join her "homegrown" campaign.

The announcement that many were expecting came on Feb. 1 when Sen. Cory Booker (D-New Jersey) tossed his hat in the ring for the White House. The former mayor of Newark, New Jersey, is running on a platform that includes criminal justice reform, plans to tackle climate change, the federal legalization of marijuana, a plan to give newborn babies savings accounts worth tens of thousands when they turn 18 and more, per The Washington Post.

He announced his bid with this very inspiring video:

California Sen. Kamala Harris' presidential bid announcement was arguably one of the most anticipated of 2019.

On Dec. 1, 2018, Harris told MSNBC that she planned to make her final decision to run in the 2020 presidential election over the holidays, but on Monday, Jan. 21, Harris took to Twitter to announce that she would officially be running for president next year, and formally kicked off her campaign with a massive rally on Jan 27.

Before entering into politics, Harris worked as a California attorney and prosecutor specializing in transnational criminal organizations. In 2015, Harris was elected to the U.S. Senate as California Democrat, making her second woman of African and Asian descent to hold the position.

Julian Castro served as Mayor of San Antonio, Texas from 2009 to 2014, before serving as the housing secretary under President Barack Obama from 2014 to 2017. Castro was one of the first ones to announce his plan to run for president, sharing a message on Dec. 12, 2018 via Twitter that he plans to set up an exploratory committee to test support for a presidential bid.

With a resume as extensive as his, it's no wonder that the Texas Democrat officially announced his presidential run on Saturday, Jan. 12 in his hometown of San Antonio.

New York Sen. Kirsten Gillibrand isn't only known for her Democratic politics, but also for being one of the key political figures supporting the #MeToo movement. On Jan. 15, Gillibrand appeared on the Late Show with Stephen Colbert to announce her official run in the 2020 presidential election by launching an exploratory committee.

"I’m going to run for president of the United States," she told Colbert. "Because as a young mom I am going to fight for other people’s kids as hard as I would fight for my own."

Since Trump took office, Gillibrand has openly spoken out against the president's policies, and has asked him to resign amid the numerous sexual misconduct allegations aimed at him, which Trump has consistently denied. Prior to winning election to the U.S. Senate, Gillibrand served in the House of Representatives from 2007 to 2009. She has held the position of a New York senator since 2010.

As a leading women's rights activist, it's safe to assume that she and Trump will have a lot to talk about come the election season.

Massachusetts Sen. Elizabeth Warren has earned a fearless reputation of speaking out against President Trump's controversial policy. Well, on Dec. 31, 2018, Warren announced via Twitter that she would launch an exploratory committee as the first step towards her 2020 presidential bid.

Prior to her political career, Warren worked as a law professor at a number of universities, and was eventually elected to the National Bankruptcy Review Commission. In 2007, Warren started taking on Wall Street directly after the infamous financial crisis and in 2012 she was elected to the U.S. Senate as a Massachusetts Democrat.

Even though Warren's impressive political resume earns her a well-deserved presidential bid, Trump may disagree. Over the past few months, the two political figures have engaged in rounds of name-calling and petty remarks, particularly in regards to Warren's Native American heritage. So, there's a good chance Warren's campaign may be one of Trump's top talking points.

Indiana Mayor Pete Buttigieg is the most recent Democrat to announce the launch of his exploratory committee for president, having shared the message early Wednesday, Jan. 23 via Twitter. Buttigieg became known in the political game when he secured his mayoral win only in his 20's, and became the first openly gay candidate for the position. Prior to becoming mayor, Buttigieg also served in the Navy as a combat veteran, and is one of the youngest faces running for president, at only 37 years old.

Although his name might not be known quite as well as his fellow candidates, this millennial politician could make waves depending on his campaign. It's all just getting started.

Similar to Buttigieg, Rep. Tulsi Gabbard is a 37-year old Hawaiian Democratic congresswoman that announced her presidential bid on Saturday, Jan. 12 while appearing on The Van Jones Show. Not only is she a young face in the political game, but she made history when she was the first Hindu member to ever be elected to U.S. Congress.

Gabbard is an Iraq war veteran currently serving on the House Foreign Affairs Committee. Before that, she worked as the vice-charwoman Democratic National Committee but eventually resigned. Although she may be one of the lesser-knowns running for president, there's a chance the United States might see its first American Samoan (and female) president.

John Delaney is both a businessman and politician serving as a United States Representative as a part of Maryland's 6th district, which he held since 2013. Delaney got a real head-start over his fellow candidates: per The New York Times, he announced his plan to run for president way, way back in July of 2017, more than three years ahead of the election.

If the 2016 presidential elections taught us anything, it's that a political background isn't apparently necessary to win the White House. Andrew Yang, founder of Venture of America, is a New York entrepreneur with an interesting proposition for the American people. According to Yang's website, the candidate proposes that the U.S. government pay $1,000 a month as a "freedom dividend" to all Americans between the ages of 18 to 64 as a form of universal income and assuage the impending job crisis in the country. Yang may arguably be a dark horse in the race, but at this point, it's unclear who will come out on top.

So there you have it, everyone. The list of Democratic nominees (official and unofficial) aren't only lengthy, but quite diverse. Oh 2020, you sure are going to be interesting.

Editor's Note: This story will continue to be updated as new candidates enter the race.