20 years ago this month, U.S. Marines began fighting the largest urban battle since the Vietnam War.

More than 12,000 American, British, and Iraqi troops fought for Fallujah, just west of Baghdad,

which had become an insurgent stronghold.

Now, in collaboration with the news organization, The War Horse, Nick Schifrin spent time with the

Marines who still remember and feel that battle like it was yesterday.

Section 60 of Arlington National Cemetery is filled with men and women who never returned

from Afghanistan and Iraq. It is filled with sacrifice. It is filled with memories.

Twenty years ago, Corporal Mike Ergo and the men of Alpha Company, First Battalion, 8th Marine

Regiment, assaulted Fallujah. Their mission take the mayor's compound in the city center.

The fight was through narrow streets.

That was incoming!

It was deadly, and as seen in this BBC footage, dangerous.

I ran off first and took a couple steps and immediately tripped and fell on my face.

And I looked to see what I'd fallen on

and it was a body of an insurgent. Then 21-year-old Ergo and the team's mission was to clear the

city of al-Qaeda-backed insurgents without overwhelming air power. So they went house to house.

Originally before we deployed, we were still concerned about winning the hearts and minds of the Iraqi people.

So we obviously didn't want to destroy it to save it.

And as we walked through the city and we're clearing it house to house,

I'd already developed the sense that I was expendable, just like my teammates were.

We spoke in the National Museum of the Marine Corps in Quantico, Virginia.

A new exhibit dedicated to the Battle for Fallujah mimics its streets, down to the trash.

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