The former president and once-again-future president, who are historically something less than besties, chatted it up before the service began. (Michelle Obama was not in attendance.)

All five living presidents were in attendance at Jimmy Carter's funeral. Here's the reception Donald Trump received from other dignitaries.

One of the first calls Obama made after U.S. forces killed Osama bin Laden in 2011 was to George W. Bush to spread the word that the mission had been accomplished, said Kate Andersen Brower, author of “Team of Five: The Presidents Club in the Age of Trump.”