An emotional morning ceremony to mark the tenth anniversary of 9/11 at the Pentagon began at dawn with the unfurling of an enormous American flag--a replica of the one that hung in the same spot after flight 77 crashed into the building that tragic morning--and ended with the arrival of New York firefighters who biked there to commemorate the day.

Military and civilian defense leaders spoke to a small gathering of family members who've had to cope with their losses 10 years. Admiral Mike Mullen, Chairman of the Joint Chiefs of Staff, told them "these are the things the terrorists could not eradicate. They could bring down walls, but they could not bring down America. They could kill our citizens, but they could not kill our citizenship."

Vice President Biden said he admired the courage of the families. "Those in this building that day knew that this was a declaration of war by stateless actors bent on changing our way of life... who believed these horrible acts of terror could buckle our knees... could bend our will... could break us." (read more)

Former presidents, political leaders, members of Congress and presidential candidates reacted to the tenth anniversary of the September 11 terror attacks. Here is a look at what some had to say.

Former President Bill Clinton

"Our nation marks ten years since the terrible events of September 11, 2001 by remembering and honoring the lives of those who were killed and their loved ones, and the courage of those who tried to save them and of those who survived and had to begin again."

"Because we live in the most interdependent age in history, it is difficult to be open to the positive forces sweeping the world while closing our borders to the negative ones. So we also honor the service of those who have worked so hard for the last decade to keep America safe, free, and still open to people of every race, culture, and faith."

"Finally, we should offer special thanks to those who lost their loved ones, and responded by helping others in need. In so doing, they are winning the ultimate battle against terrorism-the triumph of love over hate."

Senate Majority Leader Harry Reid, D-Nev. (read more)