Former President George W. Bush has read aloud at the World Trade Center site a letter that was written by Abraham Lincoln to a mother who lost all five of her sons in the Civil War.

Bush and President Barack Obama stood in silence as a church bell rang twice on the moment when the first jetliner struck the trade center ten years ago.

Obama then read from Psalm 46, which reminds the faithful that God is a refuge and strength that dwells in "his city."

Cellist Yo Yo Ma played mournful music as relatives of the dead began entering a transformed ground zero.

The memorial opens to the public tomorrow. It sits next to a construction project where office towers, a transportation hub and a cultural center are taking shape.

The signature skyscraper is rising quickly and will be the tallest in the country when completed.

Some relatives wore solemn black suits. Others wore fire department T-shirts.

(Copyright 2011 by The Associated Press. All Rights Reserved.)