With fist bumps replacing handshakes and flags replacing spectators on the National Mall, this was an inauguration like no other in American history. Joe Biden became the 46th president of the United States, taking the oath of office on a family Bible minutes after Kamala Harris became the first female vice president. Barack Obama, George Bush, Bill Clinton, and Mike Pence were among the spectators, but Donald Trump left the capital hours earlier, becoming the first president to skip his successor's inauguration in more than 150 years. Photos from the historic day can be seen in the gallery. (More Inauguration Day stories.)