It isn’t quite like the World War II “Remember Pearl Harbor” battle cry that united Americans, but 9/11 is etched in the minds of people who were living in 2001.On that date, for the first time, America sustained an attack on home ground as never before by a foreign force. It didn’t result in an all out war involving the United States; however, it ignited a conflict with the Islamic group al-Qaeda.Nineteen members of the terrorist group hijacked four aircrafts for the purpose of suicide attacks in New York and Washington, D.C. The fourth hijacked aircraft was brought down by passengers before it reached its target.Two of the planes were flown into the twin towers of the World Trade Center in New York and a third plane crashed into the Pentagon in Washington, D.C.The attacks killed nearly 3,000 people and injured more than 6,000. Damage was estimated at $10 billion. The attacks were the most deadly in American history for police and firefighters — 343 firefighters and 72 policemen were killed.The battle against terrorist groups continues today. In response to the terrorist attacks we invaded Afghanistan in a war to rid the world of the Taliban, which supported al-Qaeda.The 16th anniversary of the attacks was Monday. There were observances to mark the anniversary. The anniversary is a reminder that we still are threatened by extremist groups and must be ever vigilant. Add to that the threat from North Korea, which may be aided by China and Russia.Will America be hit again by terrorist groups? We are better prepared as far as to the intelligence of terrorist operations, but it is impossible to have 100 percent security. A fear is that unless Congress and the president get moving to build a greater military, well armed, we are vulnerable.We certainly aren’t as united as we were after Dec. 7, 1941.