The online reservation system for the tickets was up at 9 a.m., and 5,000 were secured for various dates in just the first hour of operation.
The quick response is "what we were hoping for - that people would be interested in the site the public has not set foot in for 10 years," Joe Daniels, president and CEO of the National September 11 Memorial & Museum, told The Associated Press.
The memorial plaza opens to the public on Sept. 12, a day after the 10th anniversary.
Families of those who died in the terror attacks will have special reservations to the memorial that bears the names of 2,983 victims, including those who died at the Pentagon in Washington and aboard United Flight 93 that went down in Shanksville, Pa., plus six who perished in the 1993 bombing of the World Trade Center.
The names are inscribed on massive, waterfall-graced reflecting pools ringed by hundreds of white oak trees.
Officials have a dedicated telephone line for those who lost loved ones and want to visit.
Some have never been to ground zero. Others "never got any human remains back," Daniels said. "This is their final resting place."
The World Trade Center site is so loaded with emotion that families of victims will be welcomed into a private reception area.
Next year, when the museum opens, they will be ushered into a room surrounded by images, texts and other expressions of the outpouring of support from around the world after 9/11.
"Families are the reason why this memorial was built," Daniels said. "Facilitating their visit is absolutely our top priority; this is something that'll be difficult for them."
Planning for the eight-acre tribute started more than eight years ago. Approximately 600 people have worked to complete the memorial in time for this year's 10th anniversary.
The harmonious result does not reflect the painful tussles and disagreements that accompanied the memorial - among families, officials, politicians, architects and the public.
The current design emerged from a 2003 international competition launched by the Lower Manhattan Development Corp., a nonprofit formed to plan the reconstruction of the area.
By 2006, so many changes had been proposed that fundraising was suspended until the design and costs of the project were made more clear.
"We were building in the middle of grief and pain," Daniels told the AP on Monday. "Emotions running so high made every single decision that much more difficult."
The biggest, most controversial challenge involved how victim names would be displayed, he said.
"This one is different from any other memorial: The names are arranged by relationships victims had in life, not by alphabetical or chronological order," he said.
Thousands of next-of-kin were contacted and asked whether they wished their loved one's name to be placed near any other.
Two etched side-by-side into the stone tell one of the most heartwrenching stories of Sept. 11.
Abigail Ross Goodman lost her father, Richard Ross, who was on American Airlines Flight 11 that crashed into the north tower - also killing her best friend, Stacy Lee Sanders.
Goodman's family requested that her father's name be placed next to her best friend's.
Lee Ielpi, president of the September 11th Widows and Victims' Families Association, is a retired New York firefighter who carried the body of his firefighter son, Jonathan, from the rubble. He wanted the names of two friends side-by-side - John Vigiano Jr., a firefighter, and his younger brother Joe, a police detective. Ielpi said he lost a total of about 90 good friends, and his best friend - his son.
"Now that we'll be able to walk on that special ground, I cannot tell you how powerful it is," Ielpi said. "There's no words to express the feeling listening to that water - it's powerful, it's a whole acre. When you listen to it, you can hear human voices."
Passes to the memorial are free, and Daniels said he expects them to be in heavy demand as 9/11 approaches.
Reservations are required because the parts of the memorial plaza open to visitors can only hold 1,500 people at a time.
Tickets are timed to avoid overcrowding. While visitors will be allowed to stay as long as they wish, they are encouraged to take about one hour, said Michael Frazier, spokesman for the memorial and museum.
The website asks visitors to pick a date and time, and to print out each pass after it's confirmed. Information provided includes directions to a location at the 16-acre trade center site where visitors must display passes.
Memorial employees will guide visitors to a screening and orientation before entering the actual memorial.
It will be open weekdays from 10 a.m. to 8 p.m. - 9 a.m. on weekends - though hours are subject to change seasonally, Frazier said.
For more on the memorial, visit 911Memorial.org.