(CNN) - On his first full day back in Washington, President-elect Barack Obama visited Arlington National Cemetery on Sunday, where he took part in a ceremony alongside Vice President-elect Joe Biden.
The two - along with their families and a huge crowd - will attend a celebratory concert Sunday afternoon at the Lincoln Memorial.
It's all part of the drum-up to Tuesday, when Obama will be inaugurated as the 44th president of the United States.
After that come the huge challenges Obama faces as president, including making good on his campaign promise to start bringing troops home from Iraq.
The visit to Arlington cemetery was a rare somber moment in the busy schedule of Obama's itinerary leading up to Inauguration Day.
Joined by Vice President-elect Joe Biden and their families, Obama helped lay a wreath at the Tomb of the Unknowns. The event lasted about 30 minutes.
The Biden and Obama families then headed to separate church services.
The Obamas, including soon-to-be first lady Michelle, daughters Sasha and Malia, and Michelle Obama's mother, Marian Robinson, attended the 19th Street Baptist Church in northwest Washington. After a reading from Psalms, an associate pastor led a prayer. "Yes we can, in the name of Jesus we pray, Amen," she said.
The president-elect is due to appear at the Lincoln Memorial at 2:30 p.m. The first families will join him. He and Biden plan to give brief speeches at the event.
The "We are One: Opening Inaugural Celebration" at the Lincoln Memorial will feature performances by Beyonce, Sheryl Crow, John Legend, Bruce Springsteen, James Taylor, U2, will.i.am and Stevie Wonder.