Trump Tower has long been a magnet for millionaires, a mecca for tourists, and a monument to one man's need to put his name on everything.
Now that its owner-occupant has been elected president, the 58-story glass tower smack-dab in the heart of Manhattan is something new: a headache for the Secret Service and the NYPD.
And with Donald Trump reportedly thinking about commuting between his Fifth Avenue penthouse and the White House, it could turn into a full-blown migraine.
"It's an unprecedented challenge," said William Bratton, who was New York City's police commissioner until two months ago.
"You are in one of the busiest cities in the world, on one of the busiest streets in the world, and one of the most well-known buildings in the world."
Jonathan Wackrow, who was a Secret Service agent on three presidential details, said he has no doubt the agency and the NYPD can meet the challenge.
"Trump Tower will be secure. Period. That's not even a question," he said. "The bigger issue here is the impact that those security measures will have on the people of New York."
Other presidents have used retreats — the compound in Kennebunkport, Maine, or the ranch in Crawford, Texas, for the Bushes — but they were in easily protected locations.
Trump Tower, on the other hand, has hundreds of tenants in 263 apartments, according to its website. That's on top of 26 floors of offices and a five-story public atrium with stores ranging from Starbucks to Gucci.
Trump has not left the building since Thursday, and SWAT teams, barricades and sand-filled trucks are already fixtures — along with protesters. The sky above it is a no-fly zone until the inauguration at least.
"It's like living in the White House," said resident Rachel Adjmi Kaimowitz, who voted for Trump but isn't thrilled about all the new security in her building.
"It's distracting, it's nerve-wracking, it's a big problem."
Law enforcement agencies are meeting this week to discuss plans for securing the skyscraper going forward. Possible scenarios include closing lanes on Fifth Avenue, home to Tiffany's and other world-famous retailers, NBC New York reported.
New Yorkers can also expect to see restrictions on the side streets, bomb-sniffing dogs on the sidewalks and security booths popping up around the building, Bratton said. When there are large demonstrations, a section of Fifth Avenue may be shut down altogether, he said.
All of it takes money, but how much is unclear. A senior NYPD official said the costs will be "very significant." and another source estimated the price tag will be tens of millions of dollars.
In a statement, the Secret Service said it has a long relationship with the NYPD "involving large-scale complex security operations."
"We will continue to apply creative problem solving with our partners to achieve the highest level of security with the least amount of public impact," the agency said.
Kaimowitz is already thinking of getting far away from Trump and his tower.
"Every time you have guests that come in you have to have them check in at a certain area and there's Secret Service all over," she said. "I'm renting now and I'm considering not renting when my lease runs out. I think the people who own apartments are probably anxious to sell but they're not going to find anybody."
But Frederic Bouin, 57, who has been living in the tower since 1990, has no complaints about the security lockdown.
"It's great," he said. "It's the most secure building in the world."