Poll: Are we safer now than before Sept. 11, 2001?

NEW YORK, NY - AUGUST 17:  One World Trade Center or the "Freedom Tower" towers over lower Manhattan on August 17, 2016 in New York City. Lower Manhattan, previously dominated by the financial industry, has become one of Manhattan's top tourist destinations with memorials to the victims, shopping malls and historical landmarks. Fifteen years after the September 11, 2001 terrorist attacks, the area around Ground Zero has gone through significant changes but still carries reminders of that day when over 3,000 people were killed during the attacks in New York City and Washington, D.C.   (Photo by Spencer Platt/Getty Images)

NEW YORK, NY - AUGUST 17: One World Trade Center or the "Freedom Tower" towers over lower Manhattan on August 17, 2016 in New York City. Lower Manhattan, previously dominated by the financial industry, has become one of Manhattan's top tourist destinations with memorials to the victims, shopping malls and historical landmarks. Fifteen years after the September 11, 2001 terrorist attacks, the area around Ground Zero has gone through significant changes but still carries reminders of that day when over 3,000 people were killed during the attacks in New York City and Washington, D.C. (Photo by Spencer Platt/Getty Images)

The 15th anniversary of Sept. 11, 2001 is on Sunday.

It’s a day when Americans pause to reflect upon the events that occurred early Tuesday morning, when 2,977 people were killed in an organized terrorist attack. The attack, using hijacked airplanes, took place in New York City, at the Pentagon, and near Shanksville, Pennsylvania.

Since then, national, state and local policies have been developed in an effort to prevent another mass terror attack. Americans have had to evolve at airports in order to stave off another catastrophic event, while the face of terrorism has also changed.

Are we safer now than before Sept. 11, 2001?