U.S. President Barack Obama and first lady Michelle Obama will attend memorials Sunday at all three sites of the September 11, 2001 attacks.

The Obamas will travel to New York Sunday to attend the 10th anniversary ceremony at the National September 11 Memorial, located at the World Trade Center site.

The Obamas will then head to Shanksville, Pennsylvania for an anniversary observance of the crash of Flight 93 during the attacks 10 years ago.

Later, the president and first lady will travel to the Pentagon for a wreath-laying ceremony honoring the victims of the attack on the massive Defense Department building.

Sunday evening, Mr. and Mrs. Obama will attend a “Concert of Hope” at the Kennedy Center for the Performing Arts in Washington.

During his weekly address Saturday, Mr. Obama spoke of the acts of heroism a decade ago in New York, at the Pentagon and on United Flight 93.

Former U.S. presidents George W. Bush and Bill Clinton, along with Vice President Joe Biden, were in Shanksville, Pennsylvania Saturday for a ceremony dedicating a memorial to the victims of Flight 93, which crashed into a field during the attacks.

The memorial is made of white stone and commemorates the efforts by passengers and crew of Flight 93 to overcome their hijackers and force the plane to the ground.