Michael Arad, the architect behind the 9/11 memorial that opened a year ago this week, wanted to create a space for quiet reflection on those who died in the attacks in the midst of the chaos of New York City.

Arad's design, called Reflecting Absence, beat out 5,000 submitted proposals to become the memorial tribute at the site of the attacks that killed nearly 2,700 people. The site has now been visited by 4.5 million people.

"I wanted to capture that and create a place that allowed people to come together to reflect on what happened here, not alone but as a community in a public space where people gather and congregate," Arad told ABC News.

Arad, a native of Israel who was raised in the United Kingdom, the United States and Mexico, had only lived in New York for 2.5 years when the north and south towers of the World Trade Center complex were attacked.

"It changed who I am," he said. "I became a New Yorker because of what happened here."

Reflecting Absence, which was chosen as the winning design in January 2004, consists of a plaza containing waterfalls above reflecting pools where the original north and south towers stood. The names of all those killed on Sept. 11, 2001, and in the earlier World Trade Center attack on Feb. 26, 1993, are inscribed on bronze parapets surrounding the waterfalls.

In arranging the names, Arad and his team queried close to 3,000 families, and received more than 1,200 requests asking that certain names of people that knew each other be placed next to or near one another.

"[The names] are arranged according to what I call a system of meaningful adjacency. When you walk up to these panels, you don't see the order but, in fact, they are very carefully organized," he said.

The "survivor tree" - a callery pear saved from the rubble of the fallen World Trade Center towers - is also featured prominently in the memorial. After it was salvaged from Ground Zero, the tree was sent to a Bronx nursery, where it was not expected to survive. But it survived an uprooting and now stands 30 feet tall. It has come to symbolize hope and rebirth.

"There was just something incredibly beautiful about that story of its survival," Arad said.

Arad's ultimate goal with the memorial's centerpiece of waterfalls, which flow into the voids left by the original towers, was to create a place where visitors can experience the magnitude of the voids.

"I wanted to know: Could I bring that idea of emptiness, this continuous presence, and making absence present and visible, and tangible to the site?" he said. "And that's really what these spaces are about - making what is no longer here, here for all of us as we stand around the voids."