They are where some of America's most notorious and gruesome crimes took place — the homes where murderers like Jeffrey Dahmer and John Wayne Gacy killed or stashed their victims.
But after the police tape is removed, the bodies are buried and the blood is scrubbed away, owners of homes like those where Sharon Tate or JonBenet Ramsey were murdered must find a way to make the "crime scene stigma" go away. What do you do with your house of horrors?
"My advice is to hang on to the property, keep it in use," said Randall Bell, a real-estate economist who specializes in troubled properties. "You don't want these properties to go vacant because it tends to amplify the problems and curiosity and negative stigmas."
Bell, author of the business book "Strategy 360," helped calculate the psychological damage surrounding the properties where JonBenet Ramsey, Nicole Brown Simpson and the Heaven's Gate cult members died. Crime scenes get traffic from curious onlookers, and according to Bell, the properties typically stay on the market longer and sell below market price.
"You want to go through phases," he said. "My advice in the immediate aftermath is to let everyone get it out of their system. If anyone wants to look at the property, let 'em look at it, and let them kind of get it out of their system. When you hide the property, it just amplifies the mystique with it."
Some building owners lobby local governments to change the address, in an effort to thwart sightseers.
The California address of the LaBianca house where Charles Manson's "family" killed their last two victims was changed, as was the house where Nicole Brown Simpson and Ron Goldman were killed. The addresses were also changed at JonBenet Ramsey's house in Boulder, Colo., and the New York home that inspired the "Amityville Horror" book and movie.
"If you want to change the address, it could be a good thing. But you want to be careful with your timing," Bell said. "You don't want to do it right after the event; it just gives the media more to talk about."
Scott Michaels owns Dearly Departed Tours, a company that gives gawkers a bus-eye view of Los Angeles' famed houses of horror, including the home where Erik and Lyle Menendez killed their parents in the early 1990s. He lobbies for these notorious properties to be saved for posterity.
"Even though it may not be what everyone wants to embrace, it's still a fact, and people can't ignore the facts: These events made us. Can you imagine tearing down the Texas Book Depository?" he said, referring to the Dallas building where Lee Harvey Oswald fired the shots that killed President John F. Kennedy.
But tear them down they do. The Chicago house in which John Wayne Gacy stuffed the bodies of 27 young men under the floorboards was bulldozed a year after his crimes were discovered in 1978. The Milwaukee apartment building where Jeffrey Dahmer lured, killed and ate his victims was leveled in 1993.
The Rancho Santa Fe, Calif., mansion where 39 members of the Heaven's Gate cult donned matching black outfits and Nike sneakers to commit suicide was flattened, and the name of the street was changed by the neighbors.
The demolition of the Heaven's Gate property had to do with the building's outdated architecture, though its destruction "was certainly related to the incident," Bell said.
In 1993, the owners of the property where the Manson family killed actress Sharon Tate tore down the bungalow to build a bigger house. The property's address had been changed previously.
The passage of time helps to revive property values, too, with homeowners more likely to consider a crime part of the property's character, provided it happened a hundred years ago, said Gil Neary, the president of DG Neary Realty Ltd. in New York.
In the interim, there are buyers who come out to take advantage of the lowered price.
"There's always somebody looking for a bargain, and they'll deal with whatever comes along to get a good deal," Neary said. "Other people are more emotional and sensitive."
Businesses that are the scene of a brutal crime have a better chance to shake the stigma. Sparks Steak House in midtown Manhattan continues to operate at its same location despite the 1985 mob hit on Paul Castellano on the sidewalk outside the restaurant.
Casa Casuarina, the Miami Beach, Fla., villa where fashion designer Gianni Versace was gunned down in 1997, has become a member's-only club and boutique hotel after businessman Peter Loftin purchased the property in 2000.
The hotel makes no effort to hide the fact that a 27-year-old spree killer, Andrew Cunanan, killed Versace on the steps of the 1930s historic building.
"We try to make them forget about the negative aspect of Versace and the way, unfortunately, he was killed," said Elisa Brinkworth, a spokeswoman for the hotel.
She concedes they do have gawkers, but she said they are trying to catch a glimpse one of their famous guests, drifting through the hotel's wrought-iron gates.
Owners of crime-stigmatized properties have to "accept the realities of the situation," Bell said.
That includes gawkers.
"I think they're going to come," Michaels said. "No matter what."