JERSEY CITY, N.J. – The Twin Towers have been gone from the New York City skyline for 25 years. Yet still, when one looks across the Hudson River, standing in Jersey City staring at Manhattan, there is that feeling that something is missing.

While the World Trade Center is synonymous with New York City, it is standing across the Hudson River in Jersey City where that absence of the towers in the sky is most noticeable. It is not only the skyline that is empty here, but also the spaces of 749 people killed on 9/11 who lived in or had ties to New Jersey.

On Thursday, Sept. 10, the space in the expansive cityscape where the two towers once stood seems to hold the heaviness of the impending 25th anniversary of the Sept. 11, 2001 terror attacks.

A quarter of a century is a long time. It seems many of the young professionals eating salads and wraps at lunchtime along the river on Thursday may have never seen the version of the skyline where the towers pulled one’s eye toward their doubly commanding presence in anything but a photograph, maybe pulled out by parents, perhaps accompanied by remarks of how eerie it can be to see the steel landmark counterparts in the background, now knowing what would come.

The 25th anniversary feels different for Jersey City police officer Dineen Rackley, who found herself at the Jersey City 9/11 Memorial for the first time Thursday. She came to the riverside memorial to see the beam of twisted steel from the fallen towers and the statue, recovered from the wreckage and added to after, to feature bronze flowers, flags and caps and helmets from the various law enforcement agencies that responded to the tragedy in lower Manhattan.

Something about 25 years, Rackley said, drew her to the memorial. She wanted to see it before the crowds the anniversary will bring.

Engraved into a stone is a rendition of the New York City skyline as it was before 9/11. Looking past the etching of pre-9/11 Manhattan to today’s actual skyline behind it, one can immediately see what is missing, something that is still iconic to New York City, even after a prolonged absence.

Brian Gillespie, a retired police officer and Marine, feels that emptiness in the skyline deeply. Three of Gillespie’s bandmates in the law enforcement pipe and drum band he played with for years were killed on Sept. 11, 2001.

In Liberty State Park, Gillespie walked through the Empty Sky Memorial with his cream-colored service dog Phoenix, the long, shiny pair of walls bearing the names of those killed on 9/11 with a connection to New Jersey.

The open space between the walls frames the spot of the skyline where the Twin Towers once stood. One World Trade is a newer addition to the skyline, but it is not where the towers were, and it is different, singular and reflective.

Gillespie touched the etching in the wall where his friend and fellow drummer Richard Rodriguez’s name is carved, alongside all those killed in the attacks that had a connection to New Jersey. He calls him Richie and recalled the last time they spoke, on September 10, 2001.

Gillespie pulled out his phone and turned it to show us a picture he took of Richie in his pipe band uniform. Richie is standing in Liberty State Park, in his kilt, holding his drum, and the sky is not empty behind him. The Twin Towers are standing tall and proud. The next photo is one Gillespie took recently, standing in the same park and lining up the photograph in the same spot, reflecting just how much has changed in the past 25 years. Now, the memorial bearing Richie’s name stands in the spot where he once posed.

The Empty Sky Memorial looks out to the spot where the World Trade Center once was, yes, but it also looks forward, as does Gillespie. He looks forward and talks about his friends any chance he gets, speaking each of their names aloud. He looks forward and tries to honor his own complicated feelings each anniversary, spending the day in whichever way feels right to him that year.

Would Gillespie have liked to see the Twin Towers rebuilt? Sure, he would have loved that. But that couldn’t happen.

So maybe, the empty sky is what must remain, what holds the space for the memories of that day.