Getting your Trinity Audio player ready...

Signs of a city fitfully grasping for normalcy were inescapable Monday, underground and in the air, in silence and in the strains of a popular Civil War hymn.

Regular subway riders found blue-clad men and women, wearing orange reflector vests emblazoned with “POLICE,” much in evidence. As commuters exited the Union Station complex, designed in classic Roman style by Chicago’s Daniel Burnham, they were greeted by flags at half mast and a lone trumpeter playing “Battle Hymn of the Republic.”

As has been the case for several days, quiet, unmanned surveillance planes flew over the city. They were among the few aircraft of any sort discerned since nearby Reagan National Airport was shut. The planes looked down on streets with more police than tourists. Out-of-towners seemed outnumbered at times by the lonely gift and food kiosks near monuments and museums.

The planes, along with helicopters and a fighter jet, reminded citizens, albeit in a small way, of a city under a certain siege as it began its first full workweek since the terrorist attacks.

Streets, especially near landmarks, seemed remarkably quiet, a mix of the omnipresent police and the lack of tourists, the latter barred from many spots. One of the few large street gatherings was an accident, the result of a brief evacuation of Justice Department headquarters.

Normally, there would be steady cadres of camera-clicking tourists outside the White House. At one point in midmorning, there were a mere two visitors, both young men from Haifa, Israel, who saw last week’s World Trade Center attacks as they stood near the Staten Island ferry at the southern tip of Manhattan.

“It’s empty, the town is empty,” said Lior Lechner, 25, who said he had noticed one of the drones overhead, as well as what he thought was an F-15.

His friend, Ron Raveh, also 25, indicated that the evening before they had walked by the White House and their separate camera bags were checked for security reasons. On this morning, they were not.

“We don’t understand,” Lechner said, indicating that their Israeli experience makes them accustomed to more vigilant scrutiny.

An older couple, Edmund and Ingesorg Muenzenmayer, visiting from Germany, were conscious of the deserted streets. “It’s very bad,” said Edmund, “not just for the U.S. but for the whole world.”

The lack of visitors affected not just the more famous sites but lower-profile institutions, such as the Renwick Gallery, where a heretofore popular exhibit of the furniture of American Sam Maloof drew only a smattering of people on Monday.

As is true across the nation, flags were everywhere, on highway overpasses, on the backs of police motorcycles and in tavern windows. They were draped about maitre d’ stands at restaurants and flew atop union headquarters. A discount swimwear store even touted four mannequins in skimpy, red-white-and-blue bikinis.

The overt presence of extra security seemed to be fully accepted, especially by Troy Jensen, a police officer from Springfield, Mo., who drove to D.C. on vacation with his wife, Angela.

“It’s a terrible tragedy,” said Troy, 27. “I can understand the heightened security.”

As a blue and white helicopter flew back-and-forth above the National Mall, vendors outside the Commerce Department confronted the surely short-term economic pain exacted by the terrorism.

For a long while, a T-shirt-craving Mexican tourist represented about the only business at one gift kiosk. Nearby was a food kiosk run by Anh Dian, a Vietnamese immigrant.

“Business is completely off,” she said.

For most of her youth in Vietnam, she recalled, her mother sought to shield her from the death and destruction of the Vietnam War. On the day they escaped via a boat in 1975, she gained her most vivid sense of the mayhem.

“I come here,” she said, alluding to last week’s tragedy, “and I see it again.”