When many of us recall the tragedy of Sept. 11, 2001, the horrible images of the World Trade Center twin towers collapsing is at the center of our minds. We also recall crashes at the Pentagon and in Pennsylvania.

But there were other events connected to that day that few of us realized until recently, with the publication of a new book, “The Only Plane in the Sky.” The author and historian Garrett Graff, who spoke at a recent book signing and reading at R.J. Julia in Madison, highlighted three historic occurrences for 9-11.

First, it was the largest maritime evacuation of people in recent history, including Dunkirk, with over 500,000 people removed by an armada of public and private boats, from the southern tip of Manhattan to the New Jersey shores. Some laws were broken and private boats borrowed to accomplish this movement.

Second, it was the responsibility of primarily one man, at his first day on the job, to facilitate the immediate landing “at the nearest field” of over 4,500 commercial and private aircraft flying over or coming into U.S. airspace, in an effort to clear the skies as fast as possible.

This feat was accomplished with few major problems, which then allowed military and air traffic controllers to monitor the president’s plane (“the only plane in the sky”) and any military aircraft needed for support.

Third, some military fighter aircraft were initially quickly launched without armament. Two planes were specifically ordered to intercept and bring down Flight 93 over Pennsylvania, thought to still be in the air. With no weapons, the pilots were on a suicide mission to actually crash their planes into the airliner.

They were saved by the brave passengers of Flight 93, who by fighting the terrorists on the plane forced it to crash.

I read the book prior to the Madison event. It is a very comprehensive story on the subject of the tragedy and events that occurred on that day 18 years ago. Graff spent many years compiling comments from more than 450 people on what they remembered. The action moves back and forth among the events as they were occurring, with the result that it was difficult to put the book down.

Graff noted the dramatic 17-minute period between the first North Tower crash, which many at the time thought just an accident, and the second South Tower crash, when we realized we were actually under attack.

This book serves as an important document for the quarter of our population who are age 18 and under and do not have a memory of that day, some of whom are now fighting in wars that started when they were babies.

We are reminded of the bombing of Pearl Harbor, where many military personnel were killed, caught off guard and trapped on boats. This was different. The “bombs” were our own commercial aircraft, used to attack civilians, piloted by men willing to die.

Most striking is the confusion created by an enemy who, quite literally, attacked us from inside our own country in a manner that we had never experienced and that we are still trying to completely understand. As one of my classmates, a professor of Tibetan religious studies, said 18 years ago: “We need to know why they hate us so much.”

Ed Johnson lives in Noank.

My wife and I joined with some neighbors and visitors a few weeks ago at No Anchor Fine Foods and Provisions on Pearl Street in Noank for an excellent pasta buffet. It was followed by a short, informative talk by retired U.S. Navy Capt. Michael Hewitt, and then a feature film involving submarine warfare.

Mike served as a U.S. Navy submarine captain during the very active Cold War period, commanding the USS Jacksonville, Buffalo and Bluefish. This was followed by a term at the Pentagon before coming to Groton to command the sub tender Fulton, stationed at State Pier.

He gave us a short history of submarines, starting with the Hunley, a manually operated submersible vessel which was used in the Civil War against a Union Navy blockade. The Hunley sunk the Housatonic, but the explosive nose charge also destroyed the submarine vessel itself along with the crew.

The first U.S. powered submarine was initially designed by John Holland circa 1900, and submarines were later designed and built by the company that eventually became known as Electric Boat, which operated in Massachusetts before coming to Groton. However, in World War I, Germany was the largest user of submarines and their sinking of the British passenger liner Lusitania in 1915, with a large number of Americans on board, was a major factor in the U.S. entering that war.

Early American submarines utilized gasoline engines on the surface to charge batteries for electric propulsion when the subs were briefly submerged. Later subs were built more efficiently using diesel engines. Once again, the German Navy, this time fully supported by Hitler, had more U-boats in service during early World War II with devastating results against Britain in the Atlantic.

The tables were turned in the Pacific, with U.S. submarines accounting for sinking 30 percent of Japan’s Navy and 60% of Japanese merchant shipping, as U.S. subs were the only boats that could get close to the enemy shorelines. However, this did come at a loss of 52 U.S. subs and 3,506 men.

Today’s modern nuclear/electric submarines are capable of staying and operating submerged for long periods. They fall into two basic categories, one being the fast-attack subs, the other types being strategic ballistic missile subs (“boomers”)” whose inter-continental missiles have an accurate range of 5,000 miles.

Mike Hewitt’s discussion led to the feature movie of the evening, “Hunter-Killer,” a military adventure story about an American nuclear submarine on the hunt for another U.S. sub in distress in the Arctic Ocean. The plot involved a secret Russian coup that threatens to dismantle the world order, and Navy SEALs sneaking through enemy waters to rescue the kidnapped Russian president to prevent World War III.

It was a complicated plot but an enjoyable film, especially the depiction of life and activities on board a modern submarine.

My only active experience with submarines consisted of banging my head a few times while walking around inside the Nautilus floating museum at the local U.S. Naval Submarine Base, where it was definitely not an advantage to be 6 feet, 6 inches tall. So I literally take my hat off to those who so bravely serve on those ships.

My hat is off also to the management and staff of the No Anchor establishment for putting on a great meal and a fine program. I’m told they will be hosting similar events this season.

Ed Johnson lives in Noank.