It was a busy morning on the Bridge of the Americas in South-Central El Paso. Hundreds of drivers and pedestrians inched their way closer to the border crossing to make their way into the United States to go about their day.

It's like this every morning at the international port of entry.

But just before 6:30 am Tuesday, dozens of U.S. Customs and Border Protection agents walked single file from the screening station to the median and gathered in front of the flag pole. Shortly after, an honor guard marched to its spot near the pole, lowering their flag. Then the sounds of "Amazing Grace" on bagpipes and "Taps" on trumpet overpowered the sound of idling cars and tinny radios.

The CBP has commemorated the anniversary of the attacks on the World Trade Center and the Pentagon every year with the same solemn ceremony. Officials said they want to honor and remember the nearly 3,000 people who lost their lives on Sept. 11, 2001.

The ceremony also marks a day that changed how the agency secured our borders. The terrorist attacks brought about structural changes in the federal government. The creation of the Department of Homeland Security came after 9/11, along with the combination of the U.S. Customs Agency and the Border Patrol into Customs and Border Protection.

Agents stopped traffic in half the 14 lanes on the Bridge of the Americas during the ceremony. Drivers making their way from Mexico into the U.S. watched quietly, making the commemoration an international occasion. Officials held a moment of silence shortly before the announced start time of 6:46 a.m., the time locally of the attacks in New York on the World Trade Center, to lessen the impact of the lane closure on traffic.

The honor guard marched back toward the screening station and the dozens of agents followed. Other agents reopened the lanes of traffic once the median was clear.

And after a moment, it was like every other day on the international bridge.