Originally Published: 06 JAN 22 10:27 ET

Analysis by Chris Cillizza, CNN Editor-at-large

(CNN) -- January 6, 2021 started like lots of days on Capitol Hill for CNN reporter Daniella Diaz. She was braced for a very long day as Congress was set to formalize Joe Biden's Electoral College victory. What transpired over the next 21 hours -- rioters storming the US Capitol in an attempted coup -- was history in the making. On the anniversary of that fateful day, I reached out to Daniella to talk about her recollections -- and what memories have stayed with her. Our conversation -- conducted via email and lightly edited for flow -- is below.

Cillizza: Describe the mood at the Capitol when you arrived for work on January 6. Were people aware of the "Stop the Steal" rally? Worried about it?

Diaz: For me, I thought it was just going to be another normal day on the congressional beat. I've grown accustomed to the long days that come with this job and I didn't think this day would be any different. I was prepared to work late -- I just didn't realize when I arrived at the Capitol at 9 a.m. on Jan. 6 that it would also mean evacuating my workspace and hiding in another location just a few hours later.

As for the "Stop the Steal" rally, I wasn't concerned at all. There are protests around the Capitol all the time. It's one of the reasons being a congressional reporter is so special -- the constant reminder of the freedom of speech surrounding the building you work in every day. But as I watched CNN's coverage of the protest, I started gathering the day would be different.

Cillizza: At what point did it become clear to you that this wasn't going to be a normal day on the Hill? Was it a single moment or a series of moments?

Diaz: It was a series of moments. In my workspace on the House side of the Capitol building, I could see the protestors outside the building. And as I covered the joint session of Congress to certify the election results, I kept glancing outside to see where the protestors were and each time I looked, they were closer to the Capitol building. There were thousands of them. At the time I thought, "There's no way they'll come into the building." I was wrong.

I'll never forget the moment when police came into our workspace and told us we couldn't move because rioters were in the building. That was the moment I knew the day wasn't normal anymore. The staff locked the doors and within moments we heard the rioters in the hallways outside the workspace. It took all of 5 minutes for that to happen.

Cillizza: Where were you when the rioters actually entered the building? Did you stay there or did you go somewhere else?

Diaz: I stayed in the CNN House booth (a closet-sized space where we work when we're at the Capitol) for a few hours until police rushed in and evacuated us to another Capitol building through the basement tunnels. The rioters were just outside our workspace in the hallways of the Capitol but the wooden doors were thick and locked and they were never able to come in.

Cillizza: How long did it all last? At what point were you able to sort of go back to "normal"?

A lot of that time for me is a blur but I remember being in the workspace in the Capitol until around 3:30 p.m. when police ran in and told us we only had a few minutes to evacuate. I gathered my stuff as fast as I could and ran out with the dozen or so reporters and staff who were locked in with me. Then we stayed in another location in another Capitol building for about four more hours waiting for the all-clear to return to the Capitol. I continued to text sources and send in reporting of what I was hearing was happening. My work never stopped.

Around 7:30 p.m. on Jan. 6, police escorted us back into the Capitol building through the underground tunnels. As I walked back into the Capitol building, I saw the destruction by the Capitol rioters -- windows were broken, trash was everywhere. I didn't know the extent of the damage until later.

When I reached the CNN House booth, I dropped off my stuff and then I ran downstairs to outside the House chamber and took video of staffers cleaning the House chamber. It was hard for me to see the damage the rioters left on the historic Capitol building and watch custodial staff who keep the Capitol running every day clean it up.

After a few more hours the joint session resumed and I kept working. Around 4 a.m. on Jan. 7 is when Congress adjourned. I was stuck at the Capitol for a few more hours after that trying to find a way home because the city was on lockdown. I didn't get home until 6:30 a.m.

Cillizza: Finish this sentence: "My lasting memory of January 6 is ." Now, explain.

Diaz: "My lasting memory of January 6 is watching Capitol staff clean up the damage."

In just a few hours, mainly white rioters stormed the Capitol and desecrated the People's House. And hours later, the brown and Black custodial staff who work there every day and keep the beautiful building running cleaned it all up. It's something that stays with me and reminds me of the privilege certain people have in this country. It's something I will never forget.