Sunday marks the fourth anniversary of the terrorist attacks on New York's World Trade Center and the Pentagon. Several new programs, all airing on Sunday, explore various aspects of the tragedy.

History Channel offers "Osama's Hideouts" at 7 p.m., tracking the movements of Osama bin Laden from Pakistan through other locations. "The Man Who Predicted 9/11" follows at 8 p.m., spotlighting Morgan Stanley Dean Witter's director of security, Rick Rescorla. He predicted the attack and led hundreds to safety out of the World Trade Center's South Tower before he died in its collapse.

"Grounded on 9/11" at 9 p.m. on History Channel describes how the FAA ordered all aircraft out of the skies after two commercial jetliners were deliberately crashed into the World Trade Center.

Discovery Channel airs "The Flight That Fought Back" at 9 p.m. The program recounts what happened aboard United Airlines Flight 93. The flight crashed near Shanksville, Pa., after passengers fought for control of the plane, which the hijackers had set on a course toward the nation's capital. Kiefer Sutherland narrates.

"For the Love of Their Brother," at 3 p.m. and 9 p.m. on WHUT, tells the story of New York firefighter Stephen Siller, who had finished his shift and was en route home to Staten Island when he learned a plane had struck the World Trade Center.

With the Battery Tunnel closed to traffic, Siller ran toward the site to help, wearing 75 pounds of fire gear. He perished in the collapse of the towers.

To honor Siller's memory, his six siblings established the annual "Tunnel to Towers Run" for charity, which retraces the firefighter's final steps.

Several rebroadcasts air Sunday:

"The Anatomy of September 11th" at 1:30 p.m. on A&E offers a detailed account of the final 102 minutes before the World Trade Center's collapse, from the viewpoint of reporters and others present.

"World Trade Center: Rise and Fall of an American Icon" at 4 p.m. on History Channel explores the background of the physical and symbolic stature of the twin towers in the New York skyline.

"Inside 9/11," a two-part, four hour documentary that looks at the terrorist attacks and the events leading to them, is rebroadcast at 1 p.m. on National Geographic Channel.

-- Kathy Blumenstock