President-elect Donald Trump shook hands with his predecessor, Joe Biden, greeting him on the White House steps in his historic return to power Monday morning ... and Biden said "Welcome home."

First Lady Jill Biden and Melania Trump also exchanged pleasantries as the first families met for pre-inauguration tea, a tradition during the transfer.

Vice President-elect J.D. Vance shook hands with Kamala Harris at the White House just before Trump's arrival, as official events get underway to mark the peaceful transition of power.

Trump will take office today for his second term, only the second man to do so in U.S. history.

Trump will take the oath of office in the Capitol Rotunda, which holds about 600 people -- the event was officially moved indoors due to frigid regional winter conditions. The last time the ceremony was held indoors was for Ronald Reagan's second inauguration in 1985. Supreme Court Chief Justice John Roberts will administer the oath to Trump Monday.

Trump won the election in November ... defeating VP Kamala Harris in the Electoral College and overtaking her in the popular vote by nearly 2.3 million votes.

President Joe Biden and former presidents Barack Obama, Bill Clinton, and George W. Bush are set to attend the inauguration. Former First Ladies Jill Biden, Hillary Clinton and Laura Bush will also be in attendance -- though Michelle Obama won't be there.

Trump's inauguration is bringing out a few huge stars ... including Carrie Underwood, who will take the stage during Monday's ceremony. Rascal Flatts and Jason Aldean are set to perform at the inaugural ball later Monday, and Kid Rock, Billy Ray Cyrus and the Village People performed last night at a "victory rally."