It's been 14 years since 9/11 -- the day the Twin Towers of the World Trade Center fell, the Pentagon was partially destroyed and a field near Shanksville, Pa., became a giant hole in the ground in the tragic, coordinated terrorist attacks carried out by al-Qaeda.

Sept. 11, 2001, is a day etched in Americans' memories. We all know where we were upon hearing the news -- in class, on the phone, listening to the radio in the car -- and it's a day we will never, ever forget. The infamous day is filled with sorrow over the loss of lives and loved ones, whether they were firefighters, police officers, Port Authority officers or emergency workers, on one of the four planes or in the Twin Towers or the Pentagon. Nearly 3,000 people from 93 nations were killed that day: 2,753 people were killed in New York, 184 people were killed at the Pentagon, and 40 people were killed on Flight 93.

Country stars took to social media on Friday (Sept. 11) to commemorate the 14th anniversary of the tragedies and remember those we lost on 9/11.