By Ryan Dilley BBC News Online correspondent in New York

A month after the 11 September attacks on the World Trade Center, and the idea of returning to normal life still eludes many New Yorkers.

"Sometimes it feels like yesterday, sometimes it seems like a year ago," said Mayor Rudy Giuliani at the "Ground Zero" memorial service marking a month since the first of the hijacked airliners struck the World Trade Center.

Mayor Giuliani joined rescue workers at the ceremony

His words articulated the feelings of many in New York.

The 30 days which have followed the catastrophic collapse of the buildings have been trying for this notoriously hard-nosed city. With so many thousands of people consumed in the tumbling steel and concrete, few residents do not know someone caught up in the tragedy.

While the rest of the world seems to have turned its attention to the air strikes on Afghanistan, conversation in New York invariably still returns to the events of 11 September.

This is perhaps understandable, since so many citizens actually witnessed so much with their own eyes: the hijacked airliners on their erratic final approach, the deadly impacts and pan-caking of the landmark towers.

Raw feeling

It is rare to pass an hour without someone telling you of their experience on that late summer day.

We look each other in the eye now, can you believe that?

John McEnroe

"The building coming down, it sounded like a roaring waterfall, if that makes any sense," says one witness.

The wounds are still raw. Jokes about the tragedy which have dropped into e-mail inboxes around the world are not repeated here. The more than 4,000 people whose remains have yet to be found are still conspicuously referred to as "missing", with few locals willing to utter the d-word.

The people of New York were never as surly as legend would have outsiders believe, but even locals marvel at the change in attitudes wrought by the terror attacks.

Truly united

"We look each other in the eye now, can you believe that?" asked former tennis star John McEnroe at a charity event to help victims and their families.

Tourists flock to photograph the ruins

The sense of national unity fostered by the terror attacks has manifested itself in New York as a discernable politeness and courtesy. Perhaps following the example of those who helped out at "Ground Zero", New Yorkers rush to one another's aid far more readily than ever before.

They hold open doors, make room on subway seats and offer their place in the queue at the coffee counter.

"We've all got to help each other out now," says Camille Tokerud.

While, of course, there are lapses, even New Yorkers living miles from "the pile" - as the remains of the WTC have been named by rescue workers - catch a regular reminder of the tragedy on the wind.

Despite the passage of time, smoke still rises from the debris. Depending on the direction of the breeze, the smell of these underground fires can pluck at noses many blocks away.

Steam still billows from the devastated site