At night, the National Mall has an allure all its own, from the glow of the floodlit dome of the Capitol to the lights of the Washington Monument and Lincoln Memorial dancing off the Reflecting Pool. The air is clearer, the atmosphere quieter, the feeling more personal than during the day, when tourists crowd the famous landmarks.
So appealing is the nighttime atmosphere that it is attracting more and more company -- and couples, many of whom can be seen strolling arm in arm along the tree-lined paths that connect the historic sites.
But enticing as the Mall at night has become to locals and out-of-towners, it has also become more dangerous.
An outbreak of robberies and violent attacks has underscored an unpleasant reality that tourism officials would rather not acknowledge: The historic sites that make Washington a prime vacation destination are becoming rich hunting grounds for local criminals, especially after dark.
In the past month and a half, 12 people -- 10 of them tourists -- have been victims of armed robberies in the approximately seven-block stretch between the Washington Monument and the Smithsonian Arts and Industries Building. All of the incidents happened at night. Two of them involved sexual assaults.
"That's more crime than we've had in the past five to 10 years," said U.S. Park Police spokesman Sgt. Scott Fear, whose agency is responsible for patrolling the Mall area.
In response, city and federal law enforcement agencies have stepped up their coverage of prime tourist areas.
The surge in nighttime criminal activity not only casts a shadow over what for many visitors is a once-in-a-lifetime experience; it also threatens the city's economy. Tourism is the District of Columbia's No. 1 private industry, and the museums, galleries and public buildings along the Mall are among the most important attractions.
The Washington, D.C., Convention & Tourism Corp. estimates that 40 million people come to the National Mall & Memorial Parks every year. About 13,000 people a day exit the turnstiles at the Smithsonian Metro stop, which is near the center of the Mall and also close to where many of the recent crimes have occurred.
Teresa Gintner, 45, from Alabama, who last week was visiting Washington for the second time, said tourists sometimes made easy targets. "We're walking around with our heads in the clouds, looking at everything," said Gintner. After reading about the robberies, she still decided to head to the Mall but left it at dusk.
"It's a little disturbing as a tourist," said Elvira Vazquez, 30, who came to Washington along with five family members from South Central Los Angeles. "Coming from South Central L.A., we feel we can handle anything ... but that does make me concerned. I thought this area was safe.
"We were thinking of staying out late and waiting until they lit up the monuments. Now I'm thinking maybe we should stick together," she added, motioning toward her son and brothers, who were about 100 yards away at the base of the Washington Monument.
During the day, the Mall is abuzz with Washington workers and fanny-pack-wearing tourists -- often sweaty and sunburned, yet determined to make it to all the monuments and museums they have traveled so far to see.
But the shimmering nighttime transformation of the monuments creates a picture that, even after 41 years of living in the nation's capital and a career in the tourism industry, still gives Sue Porter goose bumps. "Where else are you going to get those backdrops?" says Porter, director of tourism and visitor services for the D.C. Chamber of Commerce.
"If somebody wants to make a special request or pop a certain question, you can always remember that it was made in the shadow of the Washington Monument," Porter says.
After-dark sightseeing has become a staple of tour agencies and attracts local residents as well as tourists.
"Our night tours are our specialty because the monuments are lit up at night and it's cooler outside," said Blair Brogan, assistant manager at City Segway Tours. More than a third of the 1,202 tours Brogan's company conducted in June were at night.
But the crime has already affected demand for nighttime tours. "We have had guests who have changed their [Mall] tours from evening tours to afternoon tours based on these crime reports," Brogan said. "I think there have been others who have purposely scheduled daytime tours because of this."
Victoria Isley, spokeswoman for the D.C. Convention & Tourism Corporation, said the robberies had had no overall effect on tourism or hotel reservations but had prompted "a handful of calls from people wanting to know about the safety and security of the area."
Until recently, the Mall was known for its safety -- at any time of day. And it's still considered safe during daylight, a place where parents can loosen the reins on their kids and women can relax the grip on their purses.
Even at night, the Mall and other tourist areas are still generally safer than some other parts of the city. Crime is highest in Southeast D.C., where the 7th District had 62 homicides in 2005.
Crime overall is on the rise in Washington. Over the last 30 days, robberies are up 18% and assaults with a deadly weapon are up 14%. July has seen an alarming 14 homicides in its first 12 days. Last year, the city had 3,502 robberies, 195 homicides and 165 sexual assaults.
"We've just had a spike in crime, and we're trying to get a handle on it," said District Police Chief Charles H. Ramsey. He has declared a crime emergency, which will give the police department the flexibility to shift officer schedules and dispatch patrols to high-risk areas.
But the city's nonvoting congressional delegate, Democrat Eleanor Holmes Norton, said "even one" crime was too many.
"How long can we go on this way before the Mall gets a reputation that would severely injure our economy?" Norton said. "How long? Not long."
Three of the robberies happened in a 48-hour period in late May, and two occurred last week. All of the May incidents were against couples, and all of the women were assaulted -- one sexually. One woman was kicked in the head and back and had to be taken to the hospital.
The May crimes may or not be connected, police say, but each time the assailants were three young, black males in dark clothing. Twice, at least one carried a semiautomatic handgun.
Last week's robberies happened Tuesday within about 15 minutes of each other near the south side of the Washington Monument. In the first incident, two women from Texas were robbed by two men in masks. One woman was sexually assaulted. In the second incident, the robbers took cash from two Missouri parents who were with their school-age children.
Norton said these crimes probably happened because criminals saw an opportunity.
"When you don't have crime in a place, you don't police it as well," she said, adding that many of the lights in the area were out.
No arrests have been made, but police say that they are investigating the robberies, that the lighting has been fixed, and that they have added more officers patrolling the Mall through the summer.
As night fell Friday, traffic on the Mall had slowed, but families were still out with their kids, people were still jogging and couples were still holding hands.
Victoria Blake, 26, and her boyfriend, Elliott Patterson, 22, both from London, had not heard of the robberies when they flew to the States last week but said that, even if they had, it would not have stopped them from coming.
"We'd be more cautious, a bit more alert," said Blake. "But we want to be able to say we've walked the Mall."