Welcome to Museum Archipelago. I'm Ian Elsner. Museum Archipelago guides you through the rocky landscape of museums. Each episode is rarely longer than 15 minutes, so let's get started.

There's a section of the Berlin Wall at the Hard Rock Cafe in Orlando, Florida. There's another in a little parklet near Grand Central Station in New York City, where office workers lean against it to make calls and drink coffee. There's even a piece of the wall in Sofia, Bulgaria, that, unusually for a city full of graffiti, looks like it's been recently pressure-washed.

Sam Holleran: The sections of the Berlin Wall just kind of stand in their new locations, whether that's in a shopping mall or in an upscale hotel or in a park... People just kind of walk around them. They know what they are, but they've disappeared into the landscape.

This is Sam Holleran. Holleran has spent his career on the question of what we do with shared public space.

Sam Holleran: Hi, my name is Sam Holleran, and I'm an artist and researcher, and I work on issues related to memorialization and public space. I, uh, I've have a background in working with design for communities, but I also have worked with, uh, a lot of different agencies and statutory agencies, including parks departments, cemetery authorities. Uh, so I've really got into ideas of urban design and, and, uh, curation of space and exhibitions through public space and through how it's negotiated the shared use of it

For a time, the Berlin Wall was the only example of such a widely scattered object. It helped that the Berlin Wall was over 100 miles long, so there was plenty of concrete to go around. The night it fell, Berliners gleefully chipped at the wall with little chisels, carrying away chunks as souvenirs.

But for several years now, Sam and his brother Max, a sociologist, have been studying the only other structure whose remains have been scattered across the world like this, although with much less celebration: the World Trade Center, destroyed in an attack on September 11th, 2001. Their new book, Scattered Steel: The Afterlife of the World Trade Center, is the result of that research.

Sam first encountered the steel from the World Trade Center, not at a museum or a memorial service, but in a posting for a small-town public art commission.

Sam Holleran: The posting said, 'We have this relic. We have a relic piece of steel from the World Trade Center, and without altering it, we request that you incorporate this into a sculpture.' And that piqued my interest. And then I started to talk to my brother Max about it and he said, "I think there's a real story there."

That story, like the story of the Berlin Wall, begins almost immediately after the towers fell. On the evening of the 9/11 attacks, the pressing goal was to clear the giant pile of rubble, already called Ground Zero, to rescue survivors. All too quickly, it was apparent that there were few survivors, and the rescue mission became a somber ritual to retrieve bodies.

Sam Holleran: The thing they're trying to do is remove lots and lots of structural steel with pulverized concrete between it, and in that pulverized concrete, there are human remains they have to sift for. And that, that happens largely at a sort of purpose-built facility at Fresh Kills in Staten Island, which is a former, uh, waste, uh, station. It's a, it's a, a landfill. They did not inter the remains of the World Trade Center in an existing landfill, but they made a new mound next to it to put all that pulverized concrete. But they also have the steel, and the steel is actually-- It's so massive that it's crushing the landfill. And so it, it's very quickly decided that a huge amount of the steel, upwards of 95%, is going to be recycled.

Sam says that most of this steel was sold to wholesalers within the first year after the attack, primarily in India, China, and Turkey. But not all of it. Even five percent of the World Trade Center is a lot of steel.

Photos from the weeks after the attack show fragments of the towers' facade still standing several stories tall - sections the workers clearing the site called the shrouds. Many workers thought these edifices might make an appropriate memorial, similar to the Kaiser Wilhelm Memorial Church in Berlin. That building, damaged in World War II, still stands as a stable ruin.

Sam Holleran: Thinking about Coventry Cathedral, the Dresden Cathedral, things that were destroyed during the Second World War, the walls of which are still standing. And of course, the arches of cathedrals - this kind of Gothic arch is very much present in the World Trade Center's design. And so those shrouds become a symbol, and there is some talk about whether those could be preserved on site, and they could stand there as a memorial themselves.

But many others, including the site administrators and the city government, wanted the site cut down to street level by December, the end of Mayor Rudolph Giuliani's term. So the shrouds came down too.

Sam Holleran: And then there's this kind of pause where some of the agencies who are involved in the search and rescue and the cleanup efforts at Ground Zero say, 'Well, we should save some of this steel.' And partly that's the FBI saying we should save it for a future criminal case that will be brought against the perpetrators, which doesn't happen. And then the other interesting part is that the Port Authority says, 'Let's keep some of it as a kind of record. We should establish an archive of what the World Trade Center buildings were architecturally, socially, as a landmark of New York City, and also as a structure.'

On May 30th, 2002, the "Last Column," a three-story length of steel spray-painted with the numbers of fire station companies, was ceremoniously extracted from Ground Zero. Today, it stands in a spacious gallery at the National September 11 Memorial & Museum, but first it was sent to what was becoming an archive of the saved steel: Hangar 17 at JFK Airport in New York City.

Sam Holleran: That steel was under tarps and in a sort of closed archive at Hangar 17 of JFK for a number of years, and then it reemerged as this kind of sacred material. They start to pick pieces of steel that are interesting or that show the kind of dynamic process of collapse - which, I think it can sound a little bit macabre to think that they're looking at steel, this thing that's supposed to be totally straight and uniform, and they're looking for pieces that have interesting bends in them, these kind of twists that show how they've been stressed. But on the other side, there is also this idea that it's not just about showing the impact and the catastrophe of the attacks, but also showing the strength of steel - because even though it is bent and twisted, it did survive.

High-security-clearance tours were occasionally given at Hangar 17, and the process of relic-making was underway behind closed doors.

As someone working at Hangar 17 put it, "These guys don't have to build a multi-million-dollar memorial. All they gotta do is bring people out here... It was just so raw and you could smell it and almost taste it."

But in the back of their minds, they also may have had a cautionary example of people profiting off of the Berlin Wall.

Sam Holleran: Even to this day, if you go to Berlin, you can find little chunks of the supposed Berlin Wall - which are maybe just pieces of concrete that have been spray-painted - in these little bags with a stapled piece of cardboard on top that says, 'Authentic section of the Berlin Wall.' And the people who were in charge in New York said, 'We're not gonna have that happen. That's absolutely not gonna happen.' On the one or two occasions that one of them turned up on eBay, they clamped down very quickly on that. So I think the idea of monetizing sections of it was something that there was a great deal of fear about, and a determination that it wouldn't happen.

So instead, the Port Authority of New York and New Jersey, the agency that developed and owned the towers, and that runs the region's bridges, tunnels, and airports, became the distributor.

Sam Holleran: After around the end of 2008, beginning of 2009, as the 10th anniversary of 9/11 was starting to come onto the horizon, there was this push for local municipalities to get these pieces of steel that had been previously stored at Hangar 17. They used their own funds to transport them from the hangar to all 50 states, and then they built them into a whole wide variety of memorials.

Which brings us to that posting that Sam saw for a small-town public art commission.

Sam Holleran: Obviously if this one small community has a piece of steel from the World Trade Center then others do too."

The process looked like this: the Port Authority created guidelines and issued a request for proposals, soliciting applications from groups interested in acquiring a piece of the World Trade Center steel for public display. Email chains, fire department magazines, and listservs helped spread the word, and by early 2009, requests were coming in. A lot of the resulting memorials were small-scale, built with very little money by artists and welders who donated their time.

Sam Holleran: In some ways, it's also just about who, who volunteered to get steel. So sometimes the people who went and brought steel back to their communities also had this odyssey of bringing the steel back everyone loves a good road story in the US and, there were a lot of people who told us road stories about driving giant multi-ton pieces of steel back to their communities, sometimes in, in trucks that were loaned to them by the local Walmart or things like that. There's a lot of folk stories wrapped up in it, and I think as time goes on, those folk stories will, will actually take on more and more, folkloric qualities.

Today these pieces of steel, about 1,800 individual relics, stand in all fifty states.

The first one I can remember coming across was at a suburban recreation complex in the city of Kennewick, Washington. It stood next to the soccer fields, with a flagpole threaded through the steel. It seemed incongruous, and I was surprised to see it there. But it turns out this is pretty typical for these memorials.

Sam Holleran: They also wanted to make sure that the pieces of the World Trade Center were in distinctly civic spaces. And what a civic space is, is something we also get into, because it gets a bit weird. It's not World War I - we don't have, like, a town square with a courthouse on it. Our cities are sprawling and spread out. The place where you might do the most important civic functions of your life might be a little one-story building surrounded by a parking lot that looks like a Pizza Hut. That could be the registrar's office, or the courthouse where you get married. Not everyone has this kind of very elegant cityscape to put their memorial in. So there was a sort of honesty about the spaces that we have as Americans where we can put these memorials.

I didn't even realize my hometown of Tallahassee, Florida, had one until I started researching this episode. It's also by a park, in front of an American Red Cross building. The steel, unbent, looks like it's about to take off from the Pentagon-shaped pedestal underneath it. It's positioned that way to be a sundial, casting shadows on key timestamps from that day.

The story of Tallahassee's memorial is typical. It was the project of Michael Terhune, a Tallahassee firefighter and paramedic who watched the towers fall on the fire station TV; he told the Tallahassee Democrat that he printed out the first list of names of the firefighters who died and set it beside a candle at the fire station. In late 2009, right in that first wave of requests before the 10th anniversary, he applied for a piece of steel, and eventually received an 11-foot beam from the south tower.

But that wasn't the end of the journey. It needed to be a public memorial, and he needed a public space to put it. Terhune spent more than a decade in what he called a bureaucratic nightmare: meetings with the city, the county, the fire department, the veterans association, all resulting in dead ends. For a while, the beam sat in a fire station, where firefighters used it as a table for checking their chainsaws and axes. He took everything home, restored it himself, and ultimately paid about half of the memorial's roughly $100,000 cost out of his own pocket, with the rest from donations and T-shirt sales.

Sam Holleran: During the course of interviewing more people who had made memorials, more firefighters and more people who worked in fire departments, I saw that the fire service often saw themselves as keepers of memory. The firefighters have their own fraternal orders - which are not just men anymore, but it is still a male-dominated profession by and large. And so they saw themselves as very well primed to keep the memory of 9/11. And I think in some ways, other people were quite happy to let the uniformed workers take that on. Because in our lives, we don't wanna think that we're vulnerable. We don't wanna think about the fact that a huge number of people who died - the majority, in fact - were just regular office workers who were opening up Excel sheets and getting their second cup of coffee. We wanna think about these tragedies as happening to people who've signed up for risky jobs, like firefighters.

And as Holleran says in the book, this also allowed the memorial commemoration to take on a broader meaning for Americans far from New York City. With so many memorials at fire stations, police precincts, and military bases, the story of the attack had already shifted: what had been an attack on American economic might, on Wall Street's global reach, became a story about first responders, and a preamble to the military sacrifices that would be expected in the War on Terror. "Never Forget" is the refrain.

In this way, the World Trade Center steel echoes pieces of the USS Maine. In 1898, the explosion of the USS Maine in Havana Harbor killed 260 sailors and pushed the United States into the Spanish-American War. When the wreck was finally raised in 1912, communities across the country requested pieces for local memorials: guns, hatches, anchors, and lengths of masts.

Sam Holleran: But the only reason I remember the USS Maine is as a kind of thing that old fogeys say in Mad Magazine when you're making fun of someone: 'Remember the Maine?' It's what Grandpa says, and no one has any idea what he's talking about.

Ian in recording: Everyone has, indeed, forgotten the Maine.

Sam Holleran: I'm always interested to see what things live on in memory. Obviously, the things that are useful to explaining how we got to be where we are in the present day are still very salient - that's the memory that we activate. And the rest of it lives up in the attic of our minds, and sometimes we pull it down, but most of the time it's just up there collecting cobwebs.

This September marks the 25th anniversary of the attacks. Three years after that, the towers will have been gone longer than they stood.

Sam Holleran: I think 25 years is enough time. I didn't feel this on the 20th anniversary. It was still fresh enough that most people who held positions of power in New York City had a lived experience of the World Trade Center standing. Less so now. I think there are plenty of people who only know it from photos and memorials, and who don't know it as a part of the landscape of their childhood or their adult life.

The people who died crossing the Berlin Wall risked their lives because the wall seemed permanent. If people living in East Germany had known the wall would come down, they wouldn't have needed to risk crossing it. And buildings made of steel seem permanent too.

Sam Holleran: I would encourage you to go and visit your local 9/11 memorial, 'cause it could be a really interesting experience. I would like to say that I've tracked them all down and I know them all, but there's so many that I really don't - and there's always a new one that I see. It's really surprising to see all the different permutations that these 1,800-plus memorials have taken.

Scattered Steel: The Afterlife of the World Trade Center by Sam and Max Holleran is out soon from Three Hills, an imprint of Cornell University Press.

This has been Museum Archipelago.