Americans are preparing to commemorate the September 11, 2001 deaths of nearly 3,000 people killed when terrorists crashed hijacked airliners into the World Trade Center in New York, the Pentagon in Washington, and a Pennsylvania field.
Ceremonies in New York and at the Pentagon will begin with moments of silence marking the exact moments 12 years ago when the airliners crashed. A 9/11 museum is nearing completion at the site where the twin towers of the trade center once stood.
President Barack Obama will attend a private Pentagon ceremony with Defense Secretary Chuck Hagel and Chairman of the Joint Chiefs of Staff General Martin Dempsey. Families of those killed in the attack will attend.
Visitors to the Flight 93 National Memorial participate in a sunset ceremony with a giant flag memorializing Flight 93, Sept. 10, 2013.
At the Flight 93 Memorial in Pennsylvania, relatives of the victims joined the National Park Service Tuesday in a groundbreaking ceremony for a visitor center at the site where 33 passengers and seven crew were killed. The center is being built on a ridge overlooking the crash site.
The White House says the president's national security team is taking measures to prevent 9/11 related attacks on the anniversary Wednesday, and to ensure that the American people and overseas facilities are protected.
Wednesday also is the first anniversary of the terrorist attack on the U.S. consulate in Benghazi, Libya. Ambassador Christopher Stevens and three other U.S. diplomats were killed.
The White House says it continues to mourn their deaths and remains committed to bringing those responsible for the Benghazi attack to justice.