The Horror It Hides:

That last bit is probably why it was a convenient place for John Wilkes Booth and his co-conspirators to plan the assassination of President Lincoln.

damienk2016/TripAdvisor "Sic semper high prices." -- a one-star Yelp review

Of course, Booth and his buddies didn't organize the murder of a president over some sushi while someone was butchering Don't Stop Believin' in the background. Back in the 1860s, it was just another boarding house owned by an old landlady named Mary Surratt. Located right down the block from Ford Theatre, it was one of many short-term apartments for struggling-actors-c*m-dumb-assassins.

Mathew Brady Falling back on a porn career wasn't an option before motion pictures.

Booth and his other conspirators lived at Surratt's boarding house from September 1864 to April 1865. When Lincoln was shot, Booth was arrested and Surratt got to pocket a security deposit. Or she would have, had she not been executed by hanging after being named as one of the co-conspirators. And if she thought her reputation couldn't be tarnished any further, now her boarding house is a monument to drunken confidence and bad vocal training.

The Horror It Hides:

Dig a little deeper and you'll find that a few feet underneath this little Berlin park lies the extensive bunker where Adolf Hitler offed himself at the end of World War II. And that modernist slide? Built right atop the crater where Hitler and Eva Braun's bodies were burned. Wheee.

The bunker is situated a little over 200 yards from the Holocaust Memorial in Berlin, and while historians never forgot where it was, they were pretty hesitant to let anyone else know. The German state only publicly identified it as the Hitler bunker in 2006, as there was a genuine fear that right-wing extremists might flock to the place. Germany may literally never live down the Holocaust, so no point in setting up a cozy meeting place for folks who want to start a second one.

Deror avi/Wiki Commons Subtle notice signs say, "No dogs, no fascists."

Not that there's a lot to see. Hitler's half-busted bunker is now sealed and buried below a parking lot of an apartment building and the playground that's been built on top. Because if neo-Nazis are going to meet, they better do it at the silliest place possible. There's still Nazi graffiti everywhere, but every bit of black fascist tagging gets meticulously crossed out with vibrant blue anti-Nazi graffiti. Ruthless efficiency takes no sides.

Roc Morin/VICE "We turned the swastikas into unicorns!"

And at least by hanging around a playground, those Nazi punks all look like pedophiles -- though we're not sure who is giving who a bad name there.

Holmes started renting out rooms in his Castle just around the time the 1893 World's Fair started, which saw a massive influx of tourists and other people whom nobody would notice if they went missing. As it turned out, that's exactly what happened to many of them after a brief spell in the Castle. Residents quickly discovered that while the outside looked all elegant and spacious, the interior housed poorly lit rooms with weird angles, secret chambers, and dead-end corridors. Holmes had designed his own Saw-like fun house torture dungeon, replete with trap doors, poison gas vents, and greased shafts leading to the basement. The basement was where Holmes had his killer toys, like an acid tank, a surgery table, and what he allegedly called an "elastic determinator," or torture rack he used to create a failed race of freakishly tall people. Everybody needs a hobby.

Illinois State Historical Library. "The Clue mansion ain't got s**t on me."

In 1884, after a banner year for bloodshed, Holmes was arrested ... for insurance fraud. Then, some smart detective remembered that he had a kickass building full of cool secret passages that were probably worth exploring. After the bodies were found, Holmes confessed immediately. According to the killer himself, he was responsible for 27 gruesome murders. According to the press, there were probably hundreds of bodies unaccounted for. However, recent experts have stated that the number of victims was probably only around a dozen or so, most of them his former employees. Whatever the reality, the legendary murder castle stood there until 1938, when it was torn down to build a post office, which we all agree sounds even more unpleasant to visit than a "Murder Castle."

The Horror It Hides:

They'd also tell you that their retirement home's parking lot is the site of the Valentine's Day Massacre, where Al Capone ordered one of the worst violent episodes of the Prohibition Era.

FBI A lot of hearts were broken that day. Some with bullets.

Set up as a lucrative whiskey deal, rival Bugs Moran's boys were led into a warehouse at the corner of Dickens and Clark. Dressed like Chicago cops, Capone's men popped up and "arrested" six mobsters and one poor random bystander. Thinking it was a routine pat-down, they lined themselves up against the garage wall, at which point machine gun bullets started flying, gruesomely executing the seven unarmed men.

The bloodied wall became such a symbol for the violence happening in Chicago that a lot of citizens regarded it as bad luck. As with most bloodstained objects. It didn't take long for the owner to just demolish the entire warehouse. However, a Canadian bar owner secretly bought the bricks and reassembled the wall in his men's room. He covered it with protective glass, painted targets over where the people were shot, and in order to get the toilet to flush, you had to pee on a target. That bar eventually closed, and though some of the wall's individual bricks were sold to collectors, most of that wall now sits in the Mob Museum in Las Vegas, because where else would you build a museum to organized crime?

Rachel James/Atlas Obscura That's not paint.

But the parking lot itself maintains no memorial or anything to this horrific event. The owners are probably hoping people will eventually forget.

Ryan Menezes Not the first time a nursing home is relying on dementia to get away with something.

The Horror It Hides:

La Villa Bella is distinct from its neighboring houses, as it was built from the ground up in the mid-'90s. That's because the owner had to destroy the previous mansion when he found out no one wanted to buy the house where the Manson family murdered Sharon Tate and four other people. Oddly, that doesn't look good on a property listing.

California Department of Corrections and Rehabilitation No one wants the house Evil Santa hit.

In fact, the only person owner Al Weintraub found after listing the property was Trent "Nine Inch Nails" Reznor, who leased the mansion and built a recording studio inside for his album The Downward Spiral. After that, Weintraub found it impossible to sell the most famous murder house in California (this was before Marilyn Manson had any money, we assume), so he decided to tear it down and start over. When Reznor found out his former house / piece of murder history was going to be bulldozed, he stole the door as a souvenir.

After building La Villa Bella on top of the cursed remnants of the Polanski house, Weintraub performed the LA equivalent of a spiritual cleansing: He sold the mansion to Jeff Franklin, creator of Full House and producer of Stuart Little, probably hoping his wholesomeness could drive out the last lingering traces of one of Hollywood's darkest chapters. However, we fear that Franklin has succumbed to the darkness. How else would you explain Fuller House?

The Horror It Hides:

But unless you live in Salem, Massachusetts, your Walgreens back lot probably wasn't the site of the Salem witch trials.

The trials were responsible for the executions of 20 goody citizens who weren't goody enough in the eyes of some Puritan dickheads. As a punishment for knowing the difference between tarragon and rosemary, most of them were executed by hanging at a spot called Gallows Hill. Ironically, given its distinctive name, for centuries, no one knew where the place actually was. The pilgrims hadn't bothered recording or even marking the location of Gallows Hill. At the time, it was probably hard to miss, what with their neighbors hanging from a tree over there.

via historyofmassachusetts.org That and the constant cries of mourning cats.

Luckily, some historians from Salem State did some digging and came to a weird discovery. Working off the notes of an old-timey lawyer, Sidney Perley, the team traced Gallows Hill to an overgrown area behind their local Walgreens where a bunch of homeless people were living. There is a ledge called "Proctor's Ledge" that could be seen for miles, and according to Professor Emerson Baker of Salem State, it made perfect sense for public executions and ghost-sightings of the wrongly executed.

Jenny Starrs/The Washington Post That pine tree is one witch's great-grandchild.

That it took three centuries to rediscover the notorious site does not exactly speak well for Salem's dedication to history, but this wasn't exactly an oversight. Professor Baker also uncovered that the city had purchased Gallows Hill in 1936 and left it unused. "They purchased this specifically to be a memorial place for the witches." In reality, the city was more keen on keeping its sordid past as murky as possible and let the site go derelict. Own up to your past, Salem. No matter how hard you try, you'll never be most famous for your Walgreens.

Isaac is pretty unassuming until you look at what's underneath. Follow him on Twitter or Instagram.

Also check out 5 Famous Cities With Creepy Secrets Hiding in Plain Sight and The Creepiest Serial Killers (Who Still Remain At Large).

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