Remains of a Day

1 hour, 42 minutes Time it took to destroy the towers, from the first impact to the second collapse

180 m.p.h. Speed at which a Boeing 707 could hit the towers but still not destroy them, under the official engineering plan

470 m.p.h., 590 m.p.h. Estimated flight speeds of the two Boeing 767 jets that hit the towers

0.9 Magnitude of the earthquake-like tremor caused by the impact of American Airlines Flight 11 hitting the north tower

1800 degrees F Estimated temperature of the fires ignited by the jet fuel

1022 degrees F Temperature at which steel loses half its strength; it melts at about 2500 degreesF

2.3 Magnitude of the tremor caused by the collapse of the north tower, measured from 21 miles away

60 Police officers killed; 37 Port Authority, 23 N.Y.P.D.

343 New York City fire fighters killed; 60 were off duty

658 Cantor Fitzgerald employees killed

10 Bystanders killed by falling debris

19,858 Body parts recovered from the site; 4,598 have been identified

379,036 Ounces of gold recovered from the Bank of Nova Scotia vault (current value: $118.5 million)

3 Auguste Rodin sculptures recovered from the rubble

144 Rings, among the 65,000 personal items recovered from ground zero. Other items include 437 watches, 77 necklaces, 119 earrings and 80 bracelets

4 Autographed baseballs found

16 People who escaped the south tower from above the floors where the plane hit

0 People who escaped the north tower from above the floors where the plane hit

18 Survivors found in the rubble: 12 fire fighters, three police officers, three civilians. All were found by Sept. 12

92 Bomb threats phoned in to police in New York City on Sept. 11

6 Looting arrests in New York City on Sept. 11; by Oct. 11, 54 more had been made

$4 billion to $6 billion Expected total payout of government compensation to victims' families

$2,235,997 Government estimate of the value — before subtracting insurance, pensions or other benefits — of a 25-year-old man with one child, making $50,000 a year at the time of his death

$1.36 million Average payment to first 25 families who applied

116,000 American flags sold by Wal-Mart on Sept. 11, 2001

6,400 American flags sold by Wal-Mart on Sept. 11, 2000

76% New York City public-school students who reported that six months later, they still frequently thought about the Sept. 11 attacks

3.6 million Estimated number of tourists who will have visited ground zero by the end of this year

Sources: FEMA, N.Y.P.D., F.D.N.Y., Port Authority of New York and New Jersey, McKinsey & Co., Office of the Chief Medical Examiner, Justice Department, FBI, New York Times, USA Today, Atlantic Monthly