Here's how 2020 Democrats announced their campaigns

U.S. Senator Kamala Harris (D-CA) speaks to her supporters at the official launch rally for her campaign as a candidate for President of the United States in 2020 in front of Oakland City Hall at Frank H. Ogawa Plaza on January 27, 2019; in Oakland.

Washington (CNN)Some of them announced in videos they posted to social media, others in TV interviews. Here's how 2020 Democrats announced their presidential campaigns and exploratory committees.

John Delaney

Delaney, a former congressman from Maryland, was the first Democrat to announce his campaign, all the way back in June 28, 2017. He launched with a Washington Post op-ed titled "Why I'm Running For President" and campaign announcement video. In his op-ed, Delaney wrote that he was running in hopes America could "rise above our broken politics and renew the spirit that enabled us to achieve the seemingly impossible."

Andrew Yang

    Yang, the founder of the nonprofit entrepreneur group Venture For America, is running on a platform of universal basic income. He filed to run for president on November 6, 2017 and gave an interview to the New York Times in February 2018 about his ideas. To highlight universal basic income, Yang said he would give one New Hampshire resident $1,000 a month from his own pocket. Jodie Fassi of Goffstown, New Hampshire, was selected, his campaign said.
    Andrew Yang, founder of Venture for America and 2020 Democratic presidential candidate, speaks during the Democratic Wing Ding event in Clear Lake, Iowa, U.S., on Friday, Aug. 10, 2018.

    Elizabeth Warren

    Sen. Warren announced a presidential exploratory committee on December 31, 2018 and released an autobiographical announcement video that laid out a campaign platform of fighting for the middle class. She spoke in the video about how incomes for working families and families of color have fallen, and about the role billionaires and corporations have played in eroding the middle class. She ends the video with the slogan "Join The Fight." Warren also spoke with press alongside her husband Bruce and dog Bailey. She formally announced her campaign on February 9 in Lawrence, Massachusetts and walked out to Dolly Parton's "9 to 5."

    Tulsi Gabbard

    Rep. Gabbard said on "The Van Jones Show" on January 11 that she intended to run, and formally launched 13 days later, on January 24, in an announcement video. An Iraq War veteran, Gabbard's video emphasizes peace. "Every time we launch these interventionist regime change wars it is not only our veterans who pay the price for that," she says. "Every single one of us pays the price." Gabbard held a launch event in Honolulu on February 2.

    Julián Castro

    Castro announced his campaign at a rally in San Antonio, where he was once mayor, on January 12. The former HUD walked out to "Turn! Turn! Turn!" by the Byrds, and said their was a "crisis of leadership" in the US during his speech. Castro made his announcement twice, in English and then in Spanish.

    Kirsten Gillibrand