9/11 Quotes: Politicians Share Memories, Reactions To September 11, 2001 (PHOTOS)

A decade after four planes were hijacked and used in an attack against the United States, many are reflecting on the events of Sept. 11, 2001.

In an op-ed for USA Today, President Barack Obama shared his thoughts on American life in the 10 years since 9/11:

Indeed, the last decade has been a challenging one for our country. But we have also seen the strength of the United States -- in cities that have refused to give in to fear; in communities that have persevered through hard economic times; and, above all, in our men and women in uniform and their families who have borne an extraordinary burden for our security and our values.

The perpetrators of those attacks wanted to terrorize us, but they are no match for our resilience. Today, our country is more secure and our enemies are weaker. Yet while we have delivered justice to Osama bin Laden and put al-Qaeda on the path to defeat, we must never waver in the task of protecting our nation.

Other leaders -- including former New York City Mayor Rudy Giuliani, former Secretary of State Condoleezza Rice and former President George W. Bush -- have also come forward to share their memories of that day and what life has been like for them in the time since. Below, a slideshow of their stories from 9/11 and the decade that followed:

Ten Years Later, Leaders Comment On 9/11