Monday marks Memorial Day, a national observance first known as Decoration Day. The first Memorial Day was observed on May 30, 1868, on the orders of General John Logan, commander of the Grand Army of the Republic. Flowers were placed on the graves of Union and Confederate soldiers at Arlington National Cemetery.

Initially meant as a time to remember those who fell during the bloody battles of our brutal Civil War, the holiday’s significance has been extended to honor all those who paid the ultimate price for our nation.

As they have done every year since 1948, soldiers of the 3rd U.S. Infantry Regiment placed flags at more than 200,000 gravestones at Arlington National Cemetery. They will remain at Arlington National Cemetery throughout the holiday weekend, making sure that the flags remain upright.

Of all the dangers facing our country, perhaps the greatest is the one that doesn’t make many headlines — our collective national amnesia.

Our history textbooks are sanitized to be politically correct and give our children little sense of the greatness of the nation they live in. In fact, our children are increasingly taught the exact opposite, that America was never great, that it was founded on evil, slavery and genocide. Our Founding Fathers are seldom mentioned unless it is part of a controversy about racism or some other scandal.

I am often struck by how many American kids have nothing good to say about their own country. Their knowledge of the sacrifices made to establish and preserve their freedom is virtually non-existent. They are the recipients of the greatest freedom, prosperity and opportunity that any society has ever produced, yet they are unaware of the price that was paid for it.

At my father’s table, I learned love of country in a way that only a Marine could teach it. Dad taught me that patriotism wasn’t a theory — it was flesh and blood, real sacrifice and pain.

All of these things — from these patriot graves and the memorials that honor them to the values they died for — are bound together, as Abraham Lincoln said, by the chords of memory. And we must never let those memories fade.

You are your children’s most important teacher. They are listening.

Explain to your children the price that was paid to stop the evil of fascism and the cancer of Soviet communism. Tell them why there was a Berlin Wall, what happened at Okinawa, on the beaches of Normandy, at Ground Zero and over the fields of Shanksville, Pennsylvania.

Take a moment this weekend to teach your children and grandchildren to love the things we love and to honor the things we honor. Finally, let’s remind ourselves that liberty is a gift from God and that each generation has paid in flesh and blood to preserve it.

As General George Patton said: “It is foolish and wrong to mourn the men who died. Rather we should thank God that such men lived.”