From *that* kiss to a former president's expressive faces, here's what analysts think of some key moments from the ceremony.

Former Vice President Mike Pence is in attendance at Trump’s inauguration, his wife, former second lady Karen, is not. Karen Pence snubbed the Trumps earlier this month at Carter’s funeral, where she ignored Melania Trump’s efforts to shake her hand.

President Donald Trump’s second inauguration seemed normal, but there were concerns about U.S. democracy lingering just beneath the surface.

George W. Bush gave fellow former president Barack Obama a friendly belly tap at the Jan. 9 funeral of Jimmy Carter, and the internet was obsessed with the viral moment.

Inauguration Day festivities brought plenty of high-profile style on everyone from incoming political figures to inauguration performers. "Good Morning America" is taking a closer look at the standout looks of the day from Ivanka Trump's sleek, deep green ensemble to Usha Vance's soft pink coat with a matching scarf.

George W. Bush gave fellow former president Barack Obama a friendly belly tap at the Jan. 9 funeral of Jimmy Carter, and the internet was obsessed with the viral moment. Experts reveal their takeaways from the viral moment when Sen. Deb Fischer's husband, Bruce, appeared to deny the vice president's handshake.

Nearly two weeks after former U.S. President Jimmy Carter died at the age of 100, public figures including President-Elect Donald Trump and former President Barack Obama, gathered to honor him.

George W. Bush gave fellow former president Barack Obama a friendly belly tap at the Jan. 9 funeral of Jimmy Carter, and the internet was obsessed with the viral moment.

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From exchanging candy to friendly belly taps, see some of the most memorable moments caught on camera between the former presidents Barack Obama and George W. Bush, and their wives Michelle Obama and Laura Bush.