Sept. 11, 2011 -- Water flowed into the footprints of the fallen World Trade Center towers, now twin reflecting pools, as the completed National September 11 Memorial opened for the first time today to family members on the 10th anniversary of the attacks.
The pools, nearly an acre each in size, are lined with bronze panels inscribed with the 2,983 names of those who died in the terror attacks Sept. 11, 2001, and the six people who died in the 1993 WTC bombing.
The memorial incorporated nearly 1,200 requests from victims' families to place the names near those of loved ones, co-workers and friends. It covers half of the 16-acre site, and contains 150 trees.
More than 400 swamp white oak trees were selected from within a 500-mile radius of the site to surround the reflecting pools. Additional trees from the Pennsylvania and Washington D.C., areas that also suffered attacks, will also be planted. Swamp white oaks turn a range of colors in the fall, and so in a few months the memorial will be protected by a canopy of amber, golden brown and pink leaves.
James Pappageorge, a firefighter who died on Sept. 11, 2001, working at Ground Zero, left behind his fiancée, Gina Pinos, who didn't have a chance to tell him she'd taken a pregnancy test the night before and was expecting a baby. Pinos said the memorial is "a good thing" because "Sept. 11 is a story that should continue to be told."
See the Memorial Here
The memorial was designed by architect Michael Arad and landscape architect Peter Walker. The two men were selected from an international design competition in 2003 that included more than 5,200 entries from 63 nations.
Arad said he wanted to make what was absent, visible.
"I think when you take in the scale of the space, and you see these close to 1,500 names that surround each pool, it's a moment of comprehension," he said. "It's not an easy moment, it shouldn't be, it's a sad moment. But it's a sad moment of understanding what happened that day. As you stand here I wanted people to be able to have that moment of quiet and thoughtful contemplation."
Rebuilding Visible at Ground Zero
Rebuilding the site has famously been a source of contention for everyone from politicians to developers, but it was many of the mourners who fought against rebuilding on what they called a sacred place.
"I think that's why it was so important that those people who felt immediately and understandably -- do nothing, leave this as a sacred site -- were wrong," said David Childs, the architect of One World Trade Center. "It was an honor of the people that died there, they were working there, to rebuild and say, 'Pick yourself up.' It's in our DNA to want to rebuild after disasters."
Progress has been slow since the buildings fell amid a series of political and bureaucratic wrangling. Now, the work never stops. Construction has been nearly ongoing year round.
"It never stops," Baroni said. "We can't afford to stop."
Right now, there are 3,500 construction workers on all four corners of the site. By the time the project ends, Baroni said, 25,000 different construction workers will have worked on it.
Baroni said the schedule is set by a series of deadlines -- and the next one is for the museum -- set to open in 2012. Soon the office building will be finished, and then the transportation hub, on which construction has yet to start.
The museum will showcase a collection of artifacts, photographs, personal effects and memorabilia, and expressions of tribute and remembrance.
Several oral histories are already available online.They include testimonies from a man who exited the south tower just before it collapsed, and the attorney in charge of the September 11th Victim Compensation Fund, which was created by Congress to provide economic relief to the families of those killed in the September 11, 2001 attacks, as well as to those who were physically injured that day. They include testimonies from a photojournalist who describes how she felt as she witnessed the south tower collapse, and a woman who put together a collection of drawings and letters children sent to fire departments after the attacks.
ABC News' Maggy Patrick contributed to this report