Two programs will mark the anniversary of the Sept. 11, 2001, terrorist attacks.

* Fairfax City will hold a commemoration at 7 p.m. Saturday at the Veterans Amphitheater next to City Hall, 10455 Armstrong St.

The event will honor victims of the attacks and members of the military who have served or are serving in Iraq and Afghanistan. Families of those service members are scheduled to help plant a tree.

There will also be a candlelight ceremony and music by the City of Fairfax Band, Fairfax High School's a cappella singers and bagpiper Steve Cochran.

For more information, call 703-385-7850.

* The National Geographic Channel will present a special on the Pentagon attack at 10 p.m. Tuesday.

The program, called "Seconds From Disaster: Pentagon 9-11," will examine such questions as: Why did the plane that hit the Pentagon not cause more damage or claim more lives? Why did people on certain floors survive while others did not? And what can be learned that might help protect people from future tragedy?

The program, which will include firsthand accounts, will show the chain of events at the Pentagon that day and explain how and why events unfolded as they did.