ATLANTA settled down to a more sober Olympic experience this weekend, resigned to the fact that during these Games the city won't, as promised, be "the safest place on earth to be".

The spirit of light exuberance and general innocence which marked opening week has now hardened into a more determined and defiant attitude.

But with America in the window of the world these Games won't be given the chance to fail. Atlanta is picking up the pieces and getting on with the show.

The shock and anger in the city at the violation of its Olympic spirit has been made more acute by the suspicion being openly expressed by federal agencies yesterday that the motives behind the bombing may be domestic.

Since the flame was ignited at the opening ceremony, there have been two views of these Olympics. The chaos and organisational kinks which have plagued competitors and journalists have been perceived as a problem for those in the world behind the chain link fences.

Outside on the streets and walkways, however, the mood has been lighter and more festive.

The only people complaining are foreigners and New Yorkers was the synthesis of the views expressed by callers to local radios last week.

For those just interested in having a good time, Centennial Olympic Park where the bombing occurred was the lodestone the point to which all paths eventually led.

Decked out with tents fun fairs, "global villages" and a novel fountain in the shape of the Olympic rings, the park had been the great common ground for this celebration, the new centre of a redrawn Atlanta.

These Games are the property of private enterprise and its chosen guests. Ordinary Atlantans have for some time suspected that the principal municipal dividend for them will be a higher profile for their city and a 21 acre park in the centre.

Saturday morning's act of domestically inspired criminality or terrorism has taken much of the lustre from both promises.

Centennial Olympic Park was an accidental success. The park had no part in the original blueprint for these Games but was designed as the city's response to Las Ramblas and the Plaza Espana in Barcelona where the world promenaded during the 1992 Games.

Hundreds of thousands of Americans paid $35 a head to help fund the park and to have their names immortalised on little red paving bricks.

Despite the evident crudeness of the device which exploded in the park on Saturday morning, it was the location which was so expertly chosen.

Understandably Atlanta has been a little jittery ever since. Police have responded to up to 100 calls from the public about suspicious packages or bags. Saturday afternoon brought more confusion as a bomb scare closed down a major downtown shopping mall and a pivotal light rail station. Bomb squad personnel carried out a controlled explosion on a suspect package at the mall but were at pains yesterday to emphasise that they subsequently found the package was harmless.

Meanwhile, the start of the track and field programme has brought drama and sporting history and hopes are high that Centennial Olympic Park will reopen some time today having been thoroughly combed for forensic evidence. Atlantans yesterday were getting back to the business of selling their city and salvaging their Games.

Other things have altered in tandem with the changing mood, however. Security has become considerably more visible and more heavy handed. Since Saturday morning, guards have been seen patrolling the streets wearing combat fatigues and carrying automatic weapons. Buildings have been checked again and again by teams of sniffer dogs and trucks bearing bomb disposal equipment have been visible at most Olympic sites.

Security officials have also resigned themselves to having to search the baggage of the 80,000 or so spectators who make their way to the Olympic stadium twice a day for the track sessions.

On Friday evening this reporter walked from his cab to his desk in the stadium without being accosted once for accreditation, tickets or a bag search.

By Saturday night, a series of bag searches and metal detector gates had to be passed through and pedestrian access to the area around the stadium had been considerably tightened.

Something was stolen from the Olympic Games over the weekend. The presence of heavily armed, gum chewing guards on every corner of every street has been a reminder of the intrusiveness of the real world.

Amidst all the talk of dreams and fulfilment and the moments of blinding glory and weary despair the Olympics don't exist in a bubble after all.

The spirit isn't as blithe as it was last week but it is stronger and more focused. Saturday's bombing emphasised just what an escape sport can be. This week Atlanta is trying harder than ever to focus its eyes on the sport.