Members of the Fire Department of New York take time to reflect during memorial observances on the 13th anniversary of the Sept. 11 terror attacks on the World Trade Center in New York, Thursday, Sept. 11, 2014.   Family and friends of those who died read the names of the nearly 3,000 people killed in New York, at the Pentagon and near Shanksville, Pennsylvania. (AP Photo/Andrew Burton, Pool)

Photos: Nation remembers 9/11

The nation pauses Thursday to mark the thirteenth anniversary of the Sept. 11, 2001 terror attack.