NEW YORK—In Manhattan’s financial district, the mood was visibly nervous Monday, as many workers returning for the first time repeatedly cast looks skyward at the gulf of light where the World Trade Center used to be.

Set against an otherworldly terrain of rubble and soot, a pedestrian-cluttered Wall Street seemed more like the hub of an authoritarian state than the financial capital of the world.

Jeeps hugged the sidewalks, hordes of journalists catching the spectacle snapped photographs from behind strict police barricades and fully-armored, camouflaged National Guard troops checked identifications at all subway exits.

Bigangi, 49, an office manager of a Wall Street bank who wished to be identified only by his last name, said that although he was not frightened to return to work, he was glad for the heightened security in the area.

“You just don’t expect something like that to happen to civilians,” he said, “Evil can strike at any time, so you have to be prepared.”

Under the 30-foot American flag draped across six of the NYSE’s Corinthian columns, a line of people waiting for the markets to open presented a unique Wall Street sight: the suited brokers clutche steaming coffees in one hand and cell phones in the other, plotting stock strategy through surgical masks to fend off the soot and smoke that still fogged the air.

Throughout the week, open spaces throughout Manhattan have served as epicenters of public grief, memorials for the dead and spaces of desperate hope for the lives of the missing.

In Washington Square Park, adjacent to New York University, the emptied water fountain sprouted thousands of candles and American flags, and hundreds have congregated for the nightly vigils held near the towering memorial arch.

Further uptown, Union Square hosted a bustling donation site over the weekend, as volunteers from NYU and elsewhere accepted overwhelming gifts of food, clothing and rescue equipment for the rescue workers and those displaced by the collapse.

Handmade posters bearing snapshots and excruciatingly detailed descriptions of the missing have multiplied exponentially since last Tuesday, as the fenced perimeter of Union Square’s lawn has become the “Wall of Hope/Mural de Esperanza” under a paper blanket of grief.

Scented candles and incense from the memorials, and traces of bitter smoke from the collapse created a sweet, heady stench that hung over the area.

With repeated urging from Mayor Rudolph W. Giuliani to continue life and business as usual, lower Manhattan seems to have settled uneasily into a routine of working, and waiting for news.

Though spontaneous debates sporadically erupt between strangers and amateur theologians, who cluster around the subway entrances off 14th Street, New Yorkers in lower Manhattan seem to have devoted more time to mourning and recovering than to contentious political rallies.

A few, however, had begun to react against the proposal of violent and prolonged military retaliation.

Actor and writer Kara Corthron, of the Manhattan-based Artist’s Network, spent Monday afternoon posting fliers that read, “Our grief is not a cry for war!”

In Union Square, peace signs and messages for tolerance proliferated around the makeshift cement monument, erected next to the towering statue of George Washington astride a war mount; reprinted articles from renowned academics Howard Zinn and Edward Said hung next to squadrons of miniature flags.

“Grief is a great excuse for horrible atrocities,” said Corthron.

“The American people have different voices, but what we’re getting from the mainstream media is so monolithic, and it all supports war.”

Others chose to forgo political discussions to concentrate on psychological healing. Nikki Boroni, a musician from Park Slope, Brooklyn, crouched on the Union Square steps in front of a sprawling series of messages, which passersby had scribbled on the ground with pastel sidewalk chalk.

“I came down to see if I could help someone who needed emotional support,” she said, staring at a queue of taxis stopped on Broadway. “But there’s just a huge pain in my heart.”

—Staff writer Mandy H. Hu can be reached at mhu@fas.harvard.edu