This Sunday, September 11, 2001, marked 15 years since our country was forever changed; devastated in the course of only one day at the hands of the worst terrorist attack in U.S. history.

"Where were you the day of 9/11?" is a question that we have all heard at one time or another in the 15 years that have passed. All Americans who were old enough to remember 9/11 have this memory etched into their minds. Devastation and fear swept across the nation as these events unfolded. An unsure and frightened country was shaken to the core of its being.

At 8:46 a.m. on that sunny, Tuesday morning of 9/11, hi-jacked American Airlines Flight 11 was deliberately flown into the North Tower of the World Trade Center.

At 9:03 a.m., a hi-jacked United Airlines plane, Flight 175, was intentionally crashed into the South Tower of the World Trade Center.

At 9:37 a.m., a third hi-jacked American Airlines plane, Flight 77, was purposefully flown into the western side of the Pentagon.

At 9:59 a.m., the South Tower of the World Trade Center collapsed.

At 10:07 a.m., a fourth hi-jacked plane, United Airlines flight 93, was deliberately crashed in Pennsylvania after passengers attempted to retake control of the aircraft.

At 10:28 a.m., The World Trade Center's North Tower collapsed.

United 93 was the only flight that did not hit its intended target. This is due to the courageous acts of the passengers aboard that were fighting to enter the cockpit to overtake the plane. The hijacker at the controls crashed the plane into a field in Shanksville, Pennsylvania, knowing he was going to be defeated by its passengers. This crash site is only a 20-minute flight from the U.S. Capitol in Washington D.C., the intended target of the terrorist hijackers.

More than 3,000 people were killed in the attacks in Washington D.C. and New York. Over 400 of those deaths included police officers and firefighters. Some families still have no biological confirmation of death due to the level of destruction. Many survivors live shattered lives, struggling with Post Traumatic Stress Disorder (PTSD) or other debilitating conditions. First responders and volunteers also suffer from a multitude of health problems, such as cancer, caused by the air quality in and around the attack site.

This year, high school freshman will learn about 9/11 as a historical event, as they were not alive during the time of the attacks.

I was 5 years old on 9/11/2001, and had just started kindergarten. I vividly recall being told the events of the morning by my teacher. All students were instructed to call our parents and go home, if possible. Children lined up to use any available phones; teachers were even handing students their personal cell phones.

My mother came to get me from school, and I had many questions about the realities of what was happening in America that morning. When we turned on the television upon arriving home, those questions faded and were replaced with horror, panic, dread and sorrow. I truly thought that the world could be ending. There was also a high concern that more terrorist tragedies had the potential to occur, instilling even more fear across America.

In the months and years following 9/11, America has become more vigilant than ever. Heightened security, awareness, and concern for prevention of these events are remnants of the effects caused by 9/11 that are still in place today. I am fortunate that I did not lose a loved one at the hands of this treacherous event, as many across the country did.

9/11 left a scar upon many people's hearts - some larger than others. The union of America after the attacks is a true testament of compassion, love, and support. America wept together while also uniting and assisting one another in spite of a atrocious and gruesome tragedy.

We must continue to unite together in the face of darkness and hatred.

We will never forget.

God Bless America.