Parents who have visited theme parks with their kids know that riding the rides (even the scary ones) is the easy part. The greater difficulty comes from having to run the gift shop gauntlet at the end of the attraction before you can see daylight. It takes an act of parental super-restraint to get your family through all the tchotchkes without opening your wallet. Our boys are all teens now, but memories of such navigation at Disney and Universal are not soon forgotten.

So I get that some had concerns upon hearing there is a gift store at the National September 11 Memorial Museum. Having visited, I can report that it is nothing like the entertainment equivalent. Traffic flow does not necessitate a visit to the gift store. In fact, its location is remote. Second, the merchandise is in keeping with the atmosphere of the museum - dignified - and most important, the sales are a sad necessity due to congressional inaction.

In round numbers, the museum cost $700 million to construct and will require about $60 million annually to operate. The federal government is providing none of that operating budget, leaving museum officials to rely on donations, the $24 (adult) admission fee, and such items as the $10.95 commemorative mugs available in the store and online.

Joe Daniels, the museum president and CEO, told me last week that the construction figure is a bit misleading.

"This was an eight-acre pit after the pile was removed and the recovery effort ended," he said. "Just to restore those eight acres back up to street level if you had no memorial, no museum, no plaza, it would have been over $300 million."

Though Daniels acknowledges that "in a perfect world, every single person could come for free," he notes that the federal government has not stepped up with support "like it does similar institutions of national import." In 2011, Sen. Daniel Inouye (D., Hawaii) introduced a bill that would have given the museum $20 million annually. But when Inouye died in 2012, so did the initiative. I can find no record of a vote being taken.

Besides, Daniels told me, there's an additional motivation for having the store: namely, reducing the black market for keepsakes.

"When we first started this project eight years ago, you would walk around the site and you have these illegal vendors selling junk related to the attacks on the street, getting up in tourists' faces," he said. "And we decided . . . if people want a souvenir, if people want a keepsake, if they want to buy a book to learn about what happened, let's be the ones to give them that opportunity and use the proceeds to keep the memorial open . . .. During our preview period, we had 42,000 9/11 stakeholders come through with the most direct connection to what happened and they were the ones buying these items to help remember their visit."

His desire to maintain decorum transcends the gift store controversy. I found the museum that just opened to the public to be appropriate, sometimes overwhelming, and emotionally draining. Much of the carnage now displayed in the museum was initially catalogued as evidence in the post-9/11 criminal probe. For the last decade, much of this has been housed in Hangar 17 at JFK airport, an 80,000-square-foot open space. These are artifacts large in both appearance and impact: two tridents that were a part of the towering lobby exterior of the twin towers, the Vesey Street ("Survivor") stairs, steel from the North Tower façade that buckled under the impact of American Airlines Flight 11, and the so-called final column, the last steel beam to be removed from what was once known as ground zero.

Seventy feet below ground level, under the two memorial pools in the footprint of the towers, is a museum within a museum where no photography is permitted. Here there are warnings of mature matter and exhibits showing people who leapt to their death. (I counted four people in one frame.) And the infamous "falling man" photograph taken by Richard Drew of the Associated Press.

This space also includes a Rolex that was on the wrist of Todd Beamer aboard Flight 93, with the date on its face forever frozen at "11." And a flight diary kept by Lorraine Bay, a flight attendant aboard the jet that crashed in Shanksville, Pa. Here, too, is a red bandana belonging to man named Welles Crowther, believed to have led many to safety from the South Tower before it collapsed.

Considering the politics and emotions of 9/11, it would have been impossible to please everyone. Some don't like the use of the terms Islamist and jihadist in a short film narrated by NBC's Brian Williams. Certain families objected when 7,390 unidentified remains were moved to a specially built repository, where they were laid to rest alongside identified remains that families chose to have moved there.

But on balance, I think the architects and designers of the space did a phenomenal job, working within a true archaeological site. As Daniels told me, the museum is housed within the bedrock foundations of the original twin tower "bathtub." You see the box columns that were the original perimeters of both towers that rose 1,350-plus feet. It is within this raw space that the museum exists. For me, one visit could never be enough. There is too much to absorb.

Against a blue backdrop created by artist Spencer Finch purposefully reminiscent of the sky on that fateful day is an appropriate quote from Virgil:

"No day shall erase you from the memory of time."

Michael Smerconish can be heard from 9 a.m. to noon on Sirius XM's POTUS Channel 124, and seen hosting "Smerconish" at 9 a.m. Saturdays on CNN. His latest book is "Talk."