Within hours of Tuesday's terrorist blitz, businesses from Coca Cola Co. in Atlanta to Ford Motor Co. in Dearborn, Mich., canceled meetings and closed down.

``This is a national tragedy, and our sympathy goes out to all those affected,'' said Nick Sharkey, a Ford spokesman.

Chrysler Group of DaimlerChrysler also shut down its U.S. headquarters in Auburn Hills, Mich., while General Motors gave workers at its world headquarters in Detroit, and in New York and Washington, the option of going home.

Printer maker Lexmark International, based in Lexington, Ky., told its 5,000 workers to go home Tuesday but said it would be back in operation Wednesday.

``We are here in the heartland, far away from the East Coast, but people will want to be with families,'' said Tim King, Lexmark spokesman.

The Mall of America in Bloomington, Minn., and The Taubman Centers, a Bloomfield Hills, Mich., company that operates 27 malls in 12 states, closed their doors. Those shopping centers that remained open beefed up security. National retailers, such as Home Depot, closed their stores in the Washington, D.C. and New York City.

Major theme parks across the country, including Disneyland Resorts and Universal Studios Hollywood shuttered their facilities and major sporting events were canceled.

In New York, the entire Wall Street area, choked by smoke and rocked by shock waves from the attacks and the subsequent collapse of the World Trade Center towers, was shut down. The Rockefeller Center buildings were mostly evacuated.

Saks Fifth Avenue closed its flagship Manhattan store, but others, including Bloomingdale's, stayed open, not only serving some shoppers but also providing a haven for employees stranded without public transportation.

``If they have to be here, we will be here,'' said Anne Keating, spokeswoman for the department store. ``Companies have ordered blankets from us for their employees to sleep on.''

Many business outside the targeted areas of New York and Washington, said they closed because they knew their workers were worried about friends and family, and about the nation's overall security.

``It is hitting everybody. It is incredible how many people have connections to people who work there,'' said Jim Eldred, chief financial officer for Cincinnati-based Human ChoiceCare, a division of Louisville, Ky.'s Humana Inc., a health care company employing 15,000 people across the country.

Some companies tried to go about their normal day of business, but most found it difficult to do so.

``People are concerned and upset ... it is not a typical day,'' said Jim Nolan, a spokesman for Mutual of Omaha. The company gave updates over its public address system as employees gathered in conference rooms to watch and listen to news reports. A moment of silence was held for those killed and injured in the attacks.