New York City Mayor Michael Bloomberg shows US Defense Secretary Leon Panetta (L) the World Trade Center 9/11 Memorial in New York Sept 6, 2011. [Photo/Agencies]

NEW YORK - New York City Mayor Michael Bloomberg outlined on Tuesday the city's progress made in the past decade in rebuilding Lower Manhattan devastated by 9/11 terrorist attacks.

Since the attacks, the city has invested $552 million in new parks, streets and water mains in the neighborhood. The residential population in Lower Manhattan has also been doubled and 19 hotels have been added over the past ten years, according to the mayor.

"I believe the re-birth and revitalization of Lower Manhattan will be remembered as one of the greatest comeback stories in American history," said Bloomberg at a breakfast at Cipriani Wall Street sponsored by the Association for a Better New York, a non-profit organization

"And I believe it will stand as our greatest monument to those we lost on 9/11 and to our unshakable faith in the moral imperative of protecting and preserving a free, open, democratic society," he added.

He said he expected Lower Manhattan to continue to grow over the next 10 years"This Sunday, as we reflect back on the past, let us remember not only the agony and anguish of the attacks, but how we channeled our pain into something positive and powerful."

The new World Trade Center site in Lower Manhattan consists of five skyscrapers (2, 3, 4, 5, and 1 WTC, or the Freedom Tower), the WTC Transportation Hub, a retail complex, and a performing arts center. The most significant is the 9/11 Memorial, slated to open on Sunday, with its two massive pools and unprecedentedly large accompanying waterfalls honoring the nearly 3,000 innocent people who lost their lives on September11, 2001, when terrorists hijacked two of passenger planes and crashed them into the twin towers at the World Trade Center in New York City.