South Twin tower immediately after the attacks (Photo Credit: By Robert on Flickr CC BY-SA 2.0 via Wikimedia Commons)

Sunday, September 11, 2016, marks the 15th anniversary of the most daring and deadliest terrorist attack on American soil. Planned and executed by Islamic extremist organization Al Qaeda, the unprovoked act of violence is what led to our ongoing "Global War On Terrorism” and changed life as we knew it, forever.

Preparation for the unprecedented attacks began early on the morning of September 11, 2001. Nineteen terrorists split into four groups, each with a trained pilot, took control of four commercial flights - United Flight 93 from New Jersey, American Flight 77 from Washington DC, and United Flight 175 and American Flight 11 from Boston. The planes were selected because they were all flying across the country, either to Los Angeles or San Francisco, and therefore had enough fuel to cause the maximum amount of damage.

Flight paths of the hijacked planes ( Image Credit: By United States Federal Bureau of Investigation via Wikimedia Commons

Though the flight passengers probably suspected something was amiss shortly after take-off, the world remained blissfully unaware of what was about to happen. At about 8:46 AM (EST), American Flight 11, which should have been heading to Los Angeles, was instead seen going towards New York City’s tallest structures — the World Trade Center’s Twin Towers. Those watching the scene from the ground thought the airplane would change directions before it was too late. But that never happened. American Airlines Flight 11 crashed right into the North Twin Tower, leaving behind a massive hole that stretched six floors.

Experts were still debating whether the “accident” was a human error or an airplane malfunction when United Flight 175 came zooming by. At 9:03 AM (EST), the plane hit the South Twin Tower, creating a massive gash all the way from the 77th to the 85th floors. At 9:37 AM (EST) American flight 77 hit the Pentagon. Shortly after, United Flight 93 crash-landed in an empty field on the outskirts of Shanksville, Pennsylvania. By now, it was evident that the United States of America had suffered a series of deadly terrorist attacks.

Aerial view of the Pentagon during rescue operations post-September 11 attack (Photo Credit: TSGT CEDRIC H. RUDISILL, USAF via Wikimedia Commons)

Though the airplane ambush was over, the nightmare was just beginning, especially for New York City’s Twin Towers. The intense fires caused by the fully-fueled planes as they hit the buildings in full force, weakened the steel support trusses that 110 floors of the Twin Towers in place. This, together with the damage caused by the planes, resulted in both towers crumbling into giant heaps of cement and steel within a few hours after the initial impact.

What is more disheartening is that even experts did not realize this could happen. Hence, while most of the estimated 16,000 - 18,000 people that were in the World Trade Center complex were safely evacuated, many first responders - firefighters, paramedics, and police, rushing in to help those injured or trapped, did not make it out. Though the Pentagon building did not suffer the same fate, the attack did result in 125 fatalities.

Freedom Tower (Photo Credit: By Anthony Quintano CC BY 2.0 via Wikimedia Commons)

All in all, 2,977 innocent people from 93 nations died that day. Things could have been worse if the terrorists on United Flight 93 had succeeded in their mission to destroy the US Capitol Building in Washington DC. According to officials, the airplane’s brave passengers and crew got wind of what the hijackers were trying to do and managed to overpower them and divert the flight to an empty field in Pennsylvania. While none of the 40 survived the crash, their courage saved the country from an even bigger catastrophe.

To show the world that the country will not be intimidated by cowardly acts of terror and honor those that perished on that fateful day, the site of the former World Trade Center is now home to both the One World Trade Center or “Freedom Tower” and a beautiful memorial. The first of three planned structures, the 1,776-feet tall building stands out like a shining beacon amidst the already impressive New York City skyline. Alongside, lies the elegant 9/11 Memorial and Museum that features twin reflecting pools with the names of every person that died in the terrorist attacks etched onto its bronze-paneled edges. A second memorial opened in Shanksville, PA last year, pays tribute to the 40 brave men and women that gave up their lives to save others.