9/11 Memorial Museum

• $24; $18 seniors 65+, U.S. veterans, U.S. college students; $15 ages 7-17; free for children under 6. Tickets are available for purchase in advance online. Admission is free for 9/11 family members, museum members, 9/11 rescue and recovery workers and active/retired U.S. Military. Admission is also free for all visitors on Tuesdays, 5 p.m. to close. A limited number of reservations can be made online two weeks in advance, starting at 9 a.m. Tuesday. Same-day tickets are available on a first-come, first-served basis at the ticket window starting at 4:30 p.m. Admission to reflecting pools is free. Guided tours available.

• 1 Albany St., New York. Visitors can currently gain access at the intersections of Liberty and Greenwich streets; Liberty and West streets; and West and Fulton streets.

• 212-266-5211, www.911memorial.org or email reservations@911memorial.org.

The walls seep with heartbreak.

In every corner, at least three of the senses are continually stimulated; four, really, if you count smell.

There is no distinct aroma inside the 9/11 Memorial Museum, but those who experienced the trauma of Sept. 11, 2001, will immediately recall the acrid stench of melted steel and burning flesh when confronted with thousands of meticulously culled artifacts from that day.

Whether it’s a wall of digital photos of “missing person” fliers – no less distressing to see 13 years later with their plaintive “Have you seen me?” messages – or the remnants of the “survivor’s stairs” that led hundreds of soot-covered World Trade Center employees out to Vesey Street to escape certain death, many visitors are stunned into silence.

Others pose in front of the incinerated frame of the FDNY Ladder Company 3 truck as if they were in the Magic Kingdom and chatter loudly about their tourist-in-New-York plans while barely glancing at the stunning enormity of a frizzled elevator motor.

But the majority seem to understand.

Here, wrenching memories are excavated for a purpose.

The geometrical mirrored exterior of the Lower Manhattan building, which sits in the shadow of the newly constructed 1 World Trade Center and steps from the outdoor reflecting pools, is in shiny contrast with the building’s somber interior.

Yes, a visit to the 9/11 Memorial Museum is an intense experience. But if it were anything less, it would have failed in its mission to pay tribute to the thousands who perished in the World Trade Center terrorist attacks of 2001 and 1993.

Since opening in late May, museum brass say more than 400,000 people have visited the tribute site. Weekend crowds remain so robust that timed entry is required for the two-hour, self-guided tours.

The immediate success of the museum is a victory for members of the nonprofit memorial foundation, who spent the past decade tangling with lawsuits, finances (the project reportedly cost $700 million, with $390 million subsidized by tax-funded grants) and arguments with families of the deceased.

While these massive and public forms of remembrance will always rankle some for any number of reasons, the 9/11 Memorial Museum is a respectful, meaningful sanctuary whose dimly lit hallways radiate solemnity.

The heart of the museum is its historical center, where photos are prohibited and tissues are readily available.

A wall of newspaper front pages from Sept. 12, 2001, stands near TV monitors showing a loop of the “Today” show and its 8:50 a.m. breaking news report of the first plane spearing the North Tower.

As difficult as it is to see the footage of that black veil of smoke shrouding the North Tower before its eventual collapse, the sense most affected in the historical center is hearing.

An alcove offers a warning sign about the harrowing content that will be heard inside. But no sign can prepare visitors for the sounds of impending death, recorded and preserved on voice mails.

The husband calling his wife from the not-yet-attacked South Tower to tell her there has been an explosion in “the other building,” followed by crackling silence.

The FDNY captain telling his crew, “We might not live through today” before they ascended the dozens and dozens of stairs in the ultimate act of bravery.

“There were just bodies coming down,” recalls one survivor on tape of the grisly sights that greeted those who managed to escape.

Outside the room, a hand-scribbled note, its desperation obvious, pleads for the rescue of 12 people trapped on the 84th floor of the North Tower.

Throughout the historical center, remnants of varying size continually jolt visitors into a state of saddened awe.

In the small space dedicated to the 9/11 attack on the Pentagon, a Navy Command Center clock, charred and battered, leans against the wall, its hands stopped at 9:37 a.m., the exact minute of impact from Flight 77.

Tattered shoes from those who evacuated the World Trade Center South Tower, as well as massive steel columns bent into unnatural shapes are more reminders of the devastation and desperation of that day.

In another room, rows of personal effects – a watch, a Blackberry, a Post-it note from a friend – help retell the stories of the people behind the tragedy.

But the museum makes plenty of room for heroes as well.

A torn and burned American flag, salvaged from the wreckage site, peers out from under glass. Stories of the hundreds of heroic NYPD and FDNY members are sprinkled throughout the exhibits.

Many who come have their own stories to share about 9/11, so a room of recording booths provides the opportunity for visitors to document their experiences.

And a few weeks ago, the museum initiated a musical tribute program. Each week, a performer representing a first responder agency will play the bagpipes outside at the Memorial, followed by a performance in the venue’s Foundation Hall.

When the 9/11 Memorial Museum opened, some controversy surrounded the inclusion of a museum store. The area is set far from the exhibition space and is primarily stocked with books about New York and the history of 9/11, T-shirts bearing the insignias of the NYPD and FDNY and the holy trinity of gift shop wares – magnets, mugs and mouse pads – stamped with the museum’s logo.

Its presence will continue to be a source of debate, but to get mired in the ancillary misses the point of the museum.

Your heart will break repeatedly. But it’s supposed to.