WHITING: It's one of those events you did not have to be there in the thick of it to be affected by it.

NARRATOR: In this episode, Adria, a nurse practitioner, and Matt, Mayo Clinic's chief security officer, discuss their experience on Sept. 11, 2001.

WHITING: I grew up in New York City, Manhattan area. I lived shortly outside the city, about 20 minutes away. On the day that we remember as 9/11, like so many people, I was at home. My husband came running into the room saying, "You're not going to believe this, but a plane has crashed into the World Trade Center." I turned the TV on and was watching it like everyone else.

I remembered the first attack on the World Trade Center back in 1993. I was very nervous to think that something more terrible than what happened in '93 was going to happen. I know my brother-in-law worked at Goldman Sachs right across (from the World Trade Center). And he had phoned my sister and said, "Something hit the first tower." My sister said: "Is this a joke? Are you joking right now?"

As the day progressed, trying to find out what was happening with everyone was a very solemn time. I'm grateful that we had still had our landlines back then. That's how we were able to communicate most of the time since our cellphones had been down. I wasn't in the city. Friends and family were. My brother-in-law was. He heard the first plane and was watching with binoculars to see what was going on.

The second plane was overhead, so he couldn't tell what kind of plane it was. He initially thought it was some sort of army plane. As he continued to watch, he started seeing people jump, and that's when he decided, "I need to get out of here."

The last time my sister heard from him was just as the first tower was starting to fall. The good news is that he made it out OK. And he and my family are grateful for that, but there are many people who didn't make it out.

Where were you, Matt, when you found out what was taking place in New York that day?

HORACE: I was in Seattle, Washington. I was still a federal agent. We were actually on a relocation trip, looking for a new home. We were moving from Washington, D.C., and there were several points of irony, even for us. No. 1: We had flown out of the same airport as the plane that hit the Pentagon. No. 2: I remembered vividly thinking that my organization's offices were right there at World Trade Center. I couldn't imagine what might have transpired with all of our employees who went to work that morning. I participated in 1993 as an investigator, so I couldn't think that anything would ever be worse than what happened in 1993 at the World Trade Center. And here we have it. Something markedly worse.

WHITING: It's something that nobody ever thought was going to happen. It's a bit surreal because you're watching TV just like everybody else. But for me personally, while I was watching TV, I was watching to see if I recognized anybody. Who do I know is coming out? Because we had so many friends — police officers, firemen, a cameraman for local news trying to record what was going on for the day because it was historic. I was trying to see who made it out, who didn't.

And the days following, flyers still stated missing people because no one wanted to say what likely was the case. I was supposed to be called into work on standby to help with anybody in the E.D. (Emergency Department) or the Burn Unit. I didn't have to go in because, unfortunately, we didn't have those survivors that we thought we were going to have. The days following, the weeks following — it was just a big change for everyone.

HORACE: I lived in New York City between 2012 and 2017. You can't be in New York City and not be impacted by that even this many years later. And I'm so struck right now this year. So much has happened during the last 24 months involving the country in elections, social justice, and galvanizing and separation. I couldn't help but think of what a colleague of mine said on LinkedIn a couple of weeks ago. He said: "On 9/11, people weren't Black or white or Hispanic, or straight or gay. On 9/11, everyone in Manhattan was ash-colored." And I thought about that. I was like, "Man, the only thing you saw of people were people covered in ash." One of my college football teammates was a firefighter who went up into a tower. He lost his life that day. I'll never forget him and what he meant to me. These things change all of us. And my entire office was wiped out. The goods, the evidence, the people, everything that we know about life in New York changed on that day.

WHITING: I vividly remember my sister saying in horror: "No one from Cantor Fitzgerald made it. Nobody made it out alive." When you think of that — 20 years later, an entire generation of kids growing up without their family — they don't recall what happened because they weren't alive to see it or maybe too young to be able to process what happened. But we have an entire company that was completely devastated. That is one of the biggest pieces that came home for me — to be working with colleagues and knowing people, and then in an instant, everybody's gone.

HORACE: Whenever I fly back, the New York City skyline obviously has changed. There's another building there now. But when you fly in and out in New York City, you just can't help it. Your mind always goes there when you go by. It's eerily changed all of our lives forever.

WHITING: Absolutely. That was one of the moments in recent history where there's a clear before and a clear after. The changes and safety and security of our country — that was the after. And so, to be able to recall what it was like before then, it's almost impossible. Because now we're just so used to all the security that you need to have. I remember afterward, you couldn't get back into work. You couldn't get back into any buildings unless you had your ID with you. That was one of the biggest changes, and security was fierce.

HORACE: From the law enforcement and security perspective, everything changed after that day. What that day showed the entire U.S. was how very vulnerable we were in different ways. Things changed dramatically in law enforcement in terms of our focus, our attention and what we applied our resources to. Security and law enforcement tend to go full circle, and we do anything and everything we can to make the public feel safe. In most cases, when you're that reactive, the measures that you're taking are not sustainable. So just like in 9/11, there are certain things we've sustained, like airport screening has gotten increased. There are other things we couldn't sustain. We can't put armed guards and police in front of every building, in every apartment. It's not sustainable, so we get back to that norm of how we live.

WHITING: Before then, we never heard of anything like "Homeland Security" and "war on terror." These phrases that just roll off the tongue. The threat level — we lived and died by what the threat level was for the day. How safe are we going to feel? What are we going to do? What is it going to be like?

HORACE: Remember also, the Department of Homeland Security didn't exist. Now the Department of Homeland Security is one of the largest organizations in government. So again, in response to things from a law enforcement security perspective, almost anything is possible. But under normal conditions, you would never take the measures to protect not just citizens of the U.S., but people who visit here and enjoy the U.S., as well.

WHITING: As a society, everybody remembers that day and their feelings that day. I'm sure it was a collective sense of shock because this is our country, our home. We were attacked in our home. Twenty years later, it still is one of those things that makes you feel like you're part of a collective human response.

HORACE: Again, the irony is that my family and I have lived in Washington, D.C., five times. So I'm reminded as I'm watching what happened even at the Pentagon on that day of how much time I've spent in traffic right next to the Pentagon. How many people I knew who work there. How many times when I was in the police department, I patrolled that area. How many times I've stood in a building across the street at the U.S. Marshals Service or the Drug Enforcement Administration. Actually, I have friends and colleagues who were working at the DEA that day at their desks and watched a plane go into the Pentagon. Again, this is just a part of our lives. I'm inextricably connected to New York City, to Washington, D.C., and the Pentagon. We had agents working in those scenes, recovering bodies and evidence, and those sorts of things. Not only are we impacted, but we're impacted in a very real way. I'm reminded almost every day of some aspect of 9/11.

WHITING: Reflecting on it 20 years later, 9/11 was one of the big reasons why I moved to the Midwest. My oldest is a 9/11 baby, and we decided to move back to the Midwest where my husband grew up because we thought it would be safer. That's the main reason why we've raised three children in Iowa. We wanted to make sure that we felt safe and give our kids the childhood that would reflect what it means to be an American in the Midwest. I don't regret that decision. Two years ago, in 2019, I brought my kids to see the 9/11 Memorial. It had been quite some time for me to be able to do that because it's so emotional to see how different everything looks, how different the atmosphere is. To me, it will always be a place where we remember the people that day.

HORACE: It was fascinating to go full circle and be involved with health care now, especially at Mayo Clinic. Because I know dozens, if not hundreds, of people who were impacted by the work that they did at ground zero in a bad way through kidney cancer, liver cancer or liver disease. And other things that people developed while working at that scene because of the carcinogens that were in the air as a result of jet fuel and building products have made hundreds of people I know in the law enforcement, fire service and emergency management sick. People have been dying ever since then from different things that they developed as a result. I'm reminded whenever I think of that building of law enforcement, fire service and EMS. I say this often: We go into places that people would run out of. We do things that people would rather not be involved with. But if you can just imagine the people who showed up that morning and saw people jumping out of buildings and ran into the building anyway. You're doing what you've been trained to do. I've never lost sight of that in terms of the public service sacrifice on 9/11.

WHITING: I agree. To have them approach the building, see this gaping hole, look at what they needed to do and still go in there, knowing the probability of them coming back out is very low. Still going in there to do what they can and do their job is just something never to be forgotten.

HORACE: People walked to Brooklyn, to Queens. Why? Because there was no other way to get there. They walked through the tunnels over in New Jersey. It's like something in a really bad movie. I know people who did that, who started walking. They weren't even near the Trade Center. They were in Uptown and other places. But the businesses were telling people: "You need to get out of Manhattan right now. Everybody leave Manhattan at once."

WHITING: All of the ferries that came to help get people off the island at the end, to try to get them over to the Jersey side to make sure that they're there safely, and all those ferry captains that answered the call. Anybody with the boat to come help evacuate people because you didn't know. If anything is to come out of 9/11, that is one thing that I really think is something that brings me peace — that everyone had this sense of unity. As a country, we stand together and we will be there side by side for each other.

NARRATOR: Where were you on Sept. 11, 2001? Share your experiences and your memories with a colleague, friend or in the comments.