Damage to the Pentagon from the 11 September attacks is due to be repaired by 11 Sept 2002 at a cost of $1 billion. While only one small section (the impact point) is seen on television as damaged, fractures to the concrete required the demolition of 400,000 square feet of office space, an area 20 times the size of the actual gap. (Demolished are rings C, D, and E between Corridors 4 and 5.) The building's previous blast-hardening programs worked to limit the damage. The two-inch-thick windows did not shatter, Kevlar sheets behind concrete walls stopped shrapnel, and the steel reinforcements kept the floors above the impact point intact long enough (35 minutes) for most workers to evacuate.--Stephen V Cole