Bicyclists zoom across the Golden Gate Bridge, wander open walkways on either side and stop for hot coffee at a cafe at the base. A bridge officer cruises by on his patrol bike.
The security at one of the country's most famous landmarks is pretty relaxed. And so are the tourists.
"If there was a place terrorists would pick, this would probably be it," admitted 33-year-old Alison Fine of Houston, who snapped photos of her family with the bridge shrouded in fog. "I'm not worried, though."
Across the country, tourists go through security scanners and remove belts and shoes before they can get close enough to the Statue of Liberty.
As millions flock to summer vacations at national landmarks _ particularly those that are embedded in our culture as symbols of freedom and the American spirit _ the level of post-Sept. 11 security often depends on the symbolism.
There have been few credible threats to the nation's icons over the past decades, authorities say _ although a New York suspect admitted to a plot to blow up the Brooklyn Bridge, and many others have talked about attacking other New York landmarks. There have been other pranks and incidents _ like when pro-Tibet protesters tried to climb up the Golden Gate in 2008, or when Greenpeace unfurled a banner atop Mount Rushmore in 2009.
The statue, the White House, Washington Monument, Liberty Bell and St. Louis' Gateway Arch still have "airport-like" security nearly a decade after Sept. 11, National Park Service spokesman David Barna said.
But U.S. officials disagree on how to strike a delicate balance between protecting our national icons from terror threats and inviting the public to visit them.
In 2003 and 2009, the General Accounting Office wrote reports saying that security at the nation's monuments needed improvement. The U.S. Park Police said something similar in 2008. The latest report in 2009 charged that the National Park Service was disorganized in the way it spends money, shares information and trains officers.
"For example, staff that are assigned security duties are generally not required to meet qualifications or undergo specialized training," the report said. "Absent a security training curriculum, there is less assurance that staff are well-equipped to effectively identify and mitigate risks at national icons and parks."
In an email sent June 3 to The Associated Press, GAO spokeswoman Laura Kopelson wrote: "According to the director of the national icon security review, NPS has not yet informed us of their actions on our recommendations in the 2009 report."
Barna said all of the recommendations have been implemented. The number of law enforcement officers within the park service _ which oversees both wild parks such as the Grand Canyon and national monuments _ has increased by 1,500 to almost 4,000 since Sept. 11.
The five most secured icons in the country "tend to have a single access entry point," Barna said, making mass casualties more of a threat.
At the base of the Washington Monument, visitors get their bags searched in a small white building at the monument's base, which houses a magnetometer. A submerged sidewalk was built after Sept. 11 all the way around the monument.
At the Statue of Liberty _ which shut down completely until 2004 and kept its crown from visitors until 2009 _ a complex system greets visitors. After they wait in a long line behind police barricades, visitors enter a giant white tent where they face security that resembles an airport terminal with six metal detectors. The tent is staffed by a private security firm and several police officers are also on hand.
Signs posted near the tent entrance warn visitors that use of cell phones and cameras is not allowed in the tent. Other signs are filled with graphics illustrating a lineup of items that cannot be taken along, including coolers, large baggage and packages.
Once on Liberty Island, visitors are required to have special passes _ acquired days or weeks earlier _ to enter the statue itself. And another security tent is set up just feet from the base of the statue.
"You just accept it," shrugged Martin Lightfoot, a 51-year-old from London. He noted he shed his belt and watch before being allowed to pass through.
"It's tighter security than I saw at the airport," he said.
Compare that to the freer and easier Golden Gate Bridge.
Visitors park in a lot on the San Francisco side of the span, while vehicles slow nearby pay tolls to drive across. Buses lumber into the lot and disgorge dozens of awe-struck tourists. From there, people can freely walk around a small park with plaques and flowers, then it's a few hundred feet to the bridge's sidewalk.
At least one Golden Gate Bridge District officer is nearby, with a mix of city police, U.S. Park police and occasional Coast Guard patrols. The Bridge district police carry guns but don't have the power to make arrests.
The number of bridge security officers increased after Sept. 11, but in recent years, the number has remained static, at 31.
It's always been a challenge to maintain security and public access simultaneously, said Golden Gate Bridge District Spokeswoman Mary Currie.
"We recently had 8,000 Girl Scouts on the bridge," she said. "Do we search the girls' backpacks? No, we have to rely on intelligence. We don't necessarily worry about an individual _ one backpack is not going to bring down the bridge."
Tourists milling around the bridge on a foggy spring day were nonplussed when asked about fears of terrorism.
"I think the worst has already happened," said Roberto Vasquez, 46, from nearby Hayward.
An even shorter response from Donna O'Brien, 62, of Davis, Calif.: "Meh."
Over the years, federal authorities have said more could be done to make the American icons safer; a delicate balance between protecting the sites and the public's need to feel free and open.
At Mount Rushmore in Keystone, S.D., rangers have received special training and have gas mats and hazmat suits in case of a chemical attack. There, rangers have received special training and have gas masks and hazmat suits on hand in case of a chemical attack.
At Nevada's Hoover Dam, security guards give a cursory check to all vehicles and a more thorough search of all trucks and buses. A sign near the parking garage tells visitors that the area is under video surveillance and that they can't bring anything that doesn't fit within the confines of a small black square.
After Sept. 11, the park service placed ugly fencing around the top of the Lincoln Memorial, which was later removed when numerous bollards were installed to prohibit anyone with a car bomb from driving into National Mall, he said.
But even to a 6-year-old, the security can make sense. Kaylee Kennedy rode back on the ferry from Liberty Island with her father, Darren, a deputy sheriff from Volusia County, Fla., after going through two security checkpoints. Kaylee said she knew why.
"They don't want anyone to shoot at the Statue of Liberty," she said.
Associated Press writer Verena Dobnik contributed to this report from New York.
EDITOR'S NOTE _ Tamara Lush is traveling the country writing about the 10th anniversary of the 9/11 attacks. Follow her on Twitter at twitter.com/tamaralush.