Yahoo TV

STORY: Biden flew to Alaska to conclude a five-day trip to India and Vietnam, and delivered remarks in a solemn ceremony in Anchorage on Monday.

Biden's decision to hold the event in Alaska, instead of Washington or New York, was a departure from what has been presidential custom.

Vice President Kamala Harris and other officials joined families of those who died on the two planes that hit the towers and on the ground at the 9/11 Memorial, which occupies the footprints of the downed building to remember the horrific day.

Across the Potomac River from Washington, Pentagon officials held the traditional event at the U.S. military's headquarters.

The attacks killed nearly 3,000 people and prompted then-President George W. Bush to launch a "global war on terror" that included a military assault on Afghanistan to find al Qaeda leader Osama bin Laden. Bin Laden eluded capture until he was killed in a U.S. raid on his Pakistan compound in 2011 ordered by then-President Barack Obama.