Most Americans, if they are old enough, still harbor stark memories of tragic events in their nation’s history: the Japanese attack on Pearl Harbor, the death of president Franklin D. Roosevelt, the assassination of president John F. Kennedy and the destruction of the World Trade Center on September 11, 2001, considered the worst act of terrorism ever carried out against the US. And they remember exactly where they were on the day when they heard the startling news.Since that horrible day 14 years ago when terrorist hijackers steered two jets into the World Trade Center’s Twin Towers, demolishing them and five outlying buildings, and killing nearly 3,000 people, we refer to that tragic destruction whenever we say “9/11.”Both the 9/11 memorial that opened in 2011 on the 10th anniversary of the attack and an accompanying underground museum that welcomed visitors last year are located at the World Trade Center (WTC) in Lower Manhattan.The National September 11 Memorial and Museum is only part of the master plan of Jewish-American architect Daniel Libeskind.When all the work is completed, the new World Trade Center, situated on 16 acres (6.5 hectares), will include office buildings, a transit hub and a performing arts center.When completed the entire site will fulfill the promise of Libeskind and others of having lifted New York City out of its depression with a firm statement that it is the city of the future.My visit to the 9/11 memorial site itself begins on the exact spot where the Twin Towers once stood, now known as Memorial Plaza. I remember the towers well; they were beacons of the colossus of Gotham town. But now in their place are recessed waterfalls cascading 9 meters down into two subterranean reflecting pools that line the Twin Towers’ original footprints (each roughly an acre in size). It is indeed a fitting and powerful memorial to those who perished that day which dawned as temperate and nearly cloudless in the eastern US Surrounding the pools are the names of people who died in the WTC attack as well as at the Pentagon just outside Washington; the passengers and crews of the hijacked airliners; the rescue personnel who died when the towers collapsed and the victims of a separate terrorist attack on the WTC in 1993. I run my hand over their names inscribed into bronze panels edging the Memorial pools and wish they were alive because I heard stories, as we all did after that dreadful day of fathers who would never see their sons and daughters play in Little League Baseball games or their children get married.The memorial’s architect was Israeli American Michael Arad – working in partnership with the landscape architect Peter Walker.Arad entitled the memorial “Reflecting Absence.” They made sure the area, with its grove of trees, highlights memory and reflection.The memorial plaza is free and open to the public. It’s a good place to meditate on the planet on which we reside.But now it’s time to go onto the 9/11 Memorial Museum itself that includes displays, artifacts, historical exhibitions, artistic expressions as well as personal reflections about that horrific day by government officials, historians, 9/11 survivors, family members of victims and journalists.Some visitors say the museum is “solemn, somber.”Some say it’s a history lesson that must be seen certainly by all Americans as well as citizens from throughout the world.Some say it’s depressing. Some say it’s a way of reminding Americans that the war on terrorism continues.A visit here convinces me it’s all that and more.This is a 21st-century museum and it meets present-day multimedia standards with its exhibits’ information on the destroyed towers, the terrorism the attack initiated, the rescue and recovery and the lives of many victims. I am told that on any given workday, up to 50,000 office workers occupied the former towers and 40,000 people passed through the complex whose construction began in 1966. Tenants started occupying its space in 1970.The museums main exhibition space lies 21 m. below street level.I, and the vast numbers of visitors that day, descend into the bowels of the earth. From here on, I notice that people talk in muffled voices.On my tour, I pass through exhibitions and educational centers, such as Memorial Hall whose title and artwork created by artist Spencer Finch is “Trying to Remember the Color of the Sky on That September Morning.” I personally recall it was blue and on my way to work as day dawned I realized the weather was temperate and nearly cloudless in the New York area.Finch’s monumental work in this hall consists of 2,983 individual squares of Fabriano Italian paper; one square for every person killed on 9/11 and the 1993 bombing.Each are hand-painted a different shade of blue.Photos and photos and more photos of those killed by the 19 al-Qaida hijackers line the wall in the In Memoriam Hall.A must is a tour of the September 11, 2001 Hall. This is where I view the main historical exhibition comprised of three parts: the day of 9/11; what led up to the attacks; and the immediate aftermath.I observe the concrete and steel remnants of the Twin Towers, personal mementos of many of those killed in the strike, including the very impressionable slurry wall and celebrated Last Column.Once in the museum itself, I recall that just before I entered, I saw the names of the victims inscribed on the panels around the twin reflecting-pools at the memorial and I wonder if I touched the names of the firefighters who rushed into the towers on 9/11 and ran upstairs into the flaming structure.You see, I’m listening to the audio recording of one of the survivors fleeing down the stairs of the building.The survivor relates how he looked into the face of a fireman “walking up the stairs to his death.And I,” he says, “was walking down to live.”Incidentally, 9/11 was the greatest single loss of rescue personnel in US history, more than 400.A demolished fire engine, sections of the steel façade of the north tower, the steel box column, remnants that anchored the Twin Towers to bedrock; those are the big eye catchers but then there are the little sights, pairs of eye glasses, packs of cigarettes, all the souvenirs of victims whose death was caused by depraved humans.“In honor of those lost do the visitors come to the memorial and museum,” I think.I left for another time a trip to the observation deck at the top of One World Trade Center, the tallest skyscraper in the Western Hemisphere and the fourth tallest in the world. The lines are long.The 104-floor skyscraper measures 417 m. tall – identical by the way with the taller of the former Twin Towers – though an illuminated antenna further increases this building’s height to 541 m. (546 m. to the tip) to commemorate America’s year of independence and its strength to endure after the dastardly attack. As my grandson, Randy, then a toddler, said in describing 9/11, “the day bad guys flew big planes into tall buildings.”Hours of admission and cost of tickets to 9/11 Museum Hours of admission are: Until September 21, 9 a.m. to 8 p.m.; September 22 to December 31, 9 to 7; May 21 to September 21, 9 to 8 – last entry an hour before closing.Tickets range from $24, ages 18-64; $18 for seniors who are 65 plus; US veterans and college students; $15 for youths, seven to 17.Free admission on Tuesdays from 5 p.m. to close, but one should arrive around 4 p.m. to obtain tickets.The author is a travel writer and lecturer, and he just published Klara’s Journey, A Novel (Marion Street Press); The Scattered Tribe: Traveling the Diaspora from Cuba to India to Tahiti and Beyond (Globe Pequot Press); A Travel Guide to Jewish Europe, 3rd edition; A Travel Guide to Jewish Russia and Ukraine and A Travel Guide to the Jewish Caribbean and South America (Pelican Publishing Company).Follow him on Twitter @bengfrank.