Today is the 10th anniversary of the 9/11 terrorist attacks, and although 10 years is like a long time, it seems like it was just yesterday that our nation was mourning the deaths of countless US citizens. Our nation will never forget this tragedy, and several country stars took to Twitter today to express their thoughts on this historic and sorrowful day. Alan Jackson -- whose 9/11 tribute song 'Where Were You (When the World Stopped Turning)' has helped to keep the memories of those who perished intact -- asked fans to share where they were on that fateful day. Darius Rucker thanked the troops for protecting our country post-9/11, and Charles Kelley of Lady Antebellum is having a bittersweet day as he tried to enjoy his birthday while paying respect to our fallen heroes. See what Jackson, Rucker, Kelley plus many other country stars had to say about 9/11 on the 10th anniversary of the terrorist attacks.