There are five buildings making up the Hotel Provincial, in the heart of New Orleans' French Quarter, and each one has its own history. Buildings 100 and 200 were built on land purchased in 1725, thanks to a grant courtesy of King Louis XV of France, developed in the 1800s and sold in 1903 to the French Market Ice Co., before being redeveloped as a hotel in 1958. Building 300 was a medicinal herb garden for a nearby military hospital through the 18th century, then a townhouse and slave housing in 1825, and finally a Confederate hospital until being redeveloped as part of the Hotel Provincial in 1967. Building 400 was a Creole store, then a hardware store and joined the Hotel Provincial in 1964. Building 500 was owned by Ursuline nuns from the early 1700s to 1830, becoming a military hospital in 1722, later burning down and being replaced by two mansions which in turn became a boarding house, a coffee house and a Civil War hospital. Not surprisingly, Building 500 is where most of the spooky action is, and the ghosts here are many and diverse. In Rooms A and B, two different soldiers appear quite boldly, speaking to guests or making eye contact before disappearing. Both soldiers love rock music and sometimes allow themselves to be photographed or recorded. Doctors and wounded soldiers also roam the building, moaning from pain and leaving mysteriously disappearing and reappearing blood stains on the bedding. Scariest of all, the elevator door sometimes opens for no reason on the second floor, revealing a garish Civil War hospital scene, and then closes.

The elegant Algonquin Hotel, designed by Goldwin Starrett and opened in 1902, was a gathering place for famous writers, actors, editors, critics and playwrights--including Dorothy Parker, Robert Benchley, Alexander Woollcott, Harold Ross, Tallulah Bankhead and Harpo Marx--whose regular "Round Table" meetings (or vicious circle, since the members thrived on gossip and pranks) helped make the hotel even more famous. But ghosts hate change, so ever since 2004, when the 174-room hotel was renovated, ghost reports by both guests and employees have proliferated. Haunting reports include members of the Round Table seen walking through the bar, lobby and dining room, mysterious footsteps in the stairwell and the repeated sound of a razor blade being tapped against a sink in a ninth-floor room.

Ghosts, man. Seriously. When a bunch of MLB players are creeped out by a hotel, that's proof enough of paranormal activity--maybe the ghost hunting isn't even necessary. Guido Pfister, who made his fortune tanning leather, and his son Charles F. Pfister spent four years and $1.5 million building the Pfister Hotel, which opened in 1893. They were dedicated to creating a "people's palace" that would serve as a grand living room for all of Milwaukee, regardless of their economic class. Today the hotel is a world-class icon at which nearly every president since Woodrow Wilson has stayed. Its Romanesque architecture is in perfect condition and the hotel houses the world's largest collection of Victorian art. But that's not all. Charles Pfister died in 1927 but--according to several guests, including some big-name baseball players--he's still there, wearing a dove-gray suit, walking up and down the grand staircase, peering down from the landing into the ballroom or the lobby, riding the elevator, disappearing through walls, playing with electronics and making a lot of noise. virtually every staff member that's ever worked there has seen Pfister beaming away at them. The Angels' CJ Wilson heard scratching in the walls. The Nationals' Bryce Harper found his clothes and a table on the other side of the room when he woke up one morning. The clock radio in the Reds' Brandon Phillips' room kept turning on by itself. The Marlins' Giancarlo Stanton says the hotel reminds him of the Disneyland Haunted House. The Giants' Edgar Renteria and Pablo Sandoval refused to stay there after losing sleep and witnessing Sandoval's iPod playing out of a speaker it wasn't even connected to. An unconnected iPod belonging to Alexi Casilla also played by itself at the hotel when he was with the Twins. The Phillies' Michael Phillips heard footsteps stomping around his room, which finally stopped when he told the ghost to make itself at home. The Dodgers' Adrian Beltre heard pounding noises on his bed, knocking on his door and the TV and A/C turned on and off repeatedly. Then-Marlins teammates Josh Johnson and Dan Meyers shared a room due to the noises they heard all night. And the Brewers' own visiting clubhouse manager Phil Rosewicz said an unnamed opposing player had fled to sleep on a couch in the Pfister's lobby after repeatedly finding the blinds and window opened.

Omni Parker House founder Harvey Parker was a perfectionist when it came to his hotel and restaurant operations, so it's hardly surprising that Parker is still around, checking on things. At his historic downtown Boston hotel, opened in 1855, Parker played host to many world-famous guests--including Charles Dickens, who stayed on the third floor, where the elevator is always heading without the button having been pushed. Parker's spirit is reportedly particularly fond of the 10th-floor annex's hallway, and has appeared outside Room 1078 as a misty apparition that solidifies as an older, heavyset man with a black mustache before disappearing. He's also been sighted in Room 1012, smiling at his guests from the end of the bed and disappearing once they smile back. Also on the 10th floor, a security guard reported that he once moved over to let a shadowy man in a stovepipe hat pass him, only to watch the man fade from sight, and bellmen have reported orbs of light floating down the hallways and disappearing and guests have complained about the sound of a rocking chair, when there are none to be found in the hotel.

The Hollywood Roosevelt Hotel, a historic Spanish-style hotel opened in 1927 at 7000 Hollywood Blvd., is most famous for hosting the first Academy Awards extravaganza and being a favorite hang-out for movie stars. But it's also the most haunted place in Los Angeles, with some big-name ghosts. Marilyn Monroe, who got her start as a model at the hotel and lived there for two years, has been seen dancing in the ballroom as well as within the mirror that has been relocated from her former room, no. 229 (where she's also been spotted), to near the mezzanine-level gift shop in the lobby, where she continues to appear in reflection. Montgomery Clift roams the eighth and ninth floor hallways playing a trombone, especially near his favorite room, no. 928, where a guest reported an unseen hand on her shoulder as she sat reading. Carole Lombard has been spotted on the 12th floor, where she and husband Clark Gable often stayed. A piano that plays by itself has appeared, along with a man in white near the piano in the Blossom Ballroom, a maid in a closet, a skipping and singing girl named Caroline near the fountain and a ghost in the pool who could be seen on security cameras but remained invisible to the security guards. Oh, and if all that isn't enough, guests often return to their rooms to find them locked from the inside.

The Congress Plaza Hotel was built to accommodate visitors to the 1893 Chicago World's Fair, and this 871-room icon on Michigan Avenue still offers the best views of the city and the lake. Over the past 130 years, however, the once posh "landmark of Chicago hospitality" has turned shabby-chic and acquired a reputation as the Windy City's spookiest venue--so scary that it's chosen annually to host national ghost hunters conventions. Here, guests still spot the gangster Al Capone, a one-time owner, crossing the hall wearing wingtips. Other ghosts include Peg Leg Johnny, a hobo who was murdered in the hotel; former, still whispering guests in the ballroom; a workman who died accidentally in the Gold Room, whose gloved hand is said to remain sticking out of the closet behind the balcony wall; a lone man who roams the eighth floor (where the elevator often mysteriously stops); and the shadowy outline of a woman on the fourth floor. Avoid Room 441, as that's the one to which security is called most often, and the 12th floor, where there is said to be a room so frightening that the door was fastened shut from the outside. But wherever your room is, take lots of photographs, as those taken at the Congress (especially in the Gold Room), often turn out with people missing from them.

The Hay-Adams Hotel, located near St. John's Episcopal Church, also known as the Church of the Presidents, occupies the site of the 1885 homes of John Milton Hay, the U.S. Secretary of State under William McKinley and Teddy Roosevelt, and Henry Adams, the writer and son of John Quincy Adams. In 1927 the homes were razed, and an Italian Renaissance-style luxury hotel was built on the site in 1928. But while the two homes are gone, the hotel seems permeated with the sad events that took place at the Adams house. The hotel is said to be haunted by Henry Adams' wife, Marian "Clover" Hooper Adams, an intellectual socialite and amateur portrait photographer (whose work has been acclaimed but who was forbidden by her husband to exhibit or publish it). Clover, who was the inspiration for Henry James' Portrait of a Lady and Daisy Miller, was also a documented occasional depressive. She died suddenly at home at age 42 in 1885 from ingesting potassium cyanide, a darkroom chemical. The death was ruled a suicide and attributed to the recent death of her father, but there has also been speculation that she may have been murdered. Clover may or may not have known that Adams had a long but unconsummated relationship with her friend and confidante, Elizabeth Sherman Cameron. Upon Clover's death, Adams destroyed most of her photographs and letters and left her entirely out of his autobiography, The Education of Henry Adams, adding to the suspicion surrounding her death. Upon her death, Adams never spoke Clover's name again, and took to restless globetrotting, but he did, however, commission Augustus Saint-Gaudens and Stanford White to create the Adams Memorial in her honor. Clover's ghost is said to wander the hotel's fourth floor hallway trailed by the scent of almond. She's also been heard crying softly in rooms and stairwells, or calling out "What do you want?" in empty rooms. Some housekeepers have reported her calling out their names and hugging them as they've cleaned rooms. Guests also often find that locked doors open and close and clock radios turn on and off. The haunting incidents occur most often in the first two weeks of December, around the anniversary of Clover's death.

Bally's Hotel occupies the 43 acres on which the Three Coins Motel stood from 1963 to 1967, when it was replaced by the Bonanza Hotel and Casino and in 1973, the 2,000-room MGM Grand. On November 1, 1980, a fire at the MGM Grand killed 85 people, including guests and employees. The hotel was rebuilt in eight months with a new additional tower and reopened as Bally's in 1985. Since then, disturbing events have been reported throughout the hotel and the casino. A strong smell of smoke often pervades the upper guest rooms, even though it's a no-smoking area. Guests often hear screaming in the stairwell, perhaps from the people who died in the MGM Grand fire. On the 17th floor hallway, a little boy can be heard crying desperately for his mother. The cries then subside into coughing and then stop abruptly. In the casino, one bank of slot machines is said to be haunted by an old woman who sometimes holds a smoking cigarette and wears a dress that is aflame. She plays two slot machines at once and vanishes instantly if approached.

Long before Washington State made marijuana legal, Seattle played host to Alice B. Toklas, perhaps equally famously known as the longtime romantic partner of Gertrude Stein and the inventor of pot brownies back in 1954. But lately, Toklas is becoming famous once again, this time for haunting the Sorrento Hotel. The classically elegant Sorrento was built in 1909 on the site of a boarding school had Toklas attended. She can be seen at the bar moving glasses, but mostly haunts the fourth floor, most specifically Room 408. How those who see her know that it's Toklas? Apparently, she wears dark-colored vintage clothing and carries a parasol...and, according to hotel management, "is very hip."

The Hotel Lawrence was built on Houston Street in Dallas in 1925 to accommodate train travelers from Union Station across the street. Since then, the economy has risen and fallen, taking the Lawrence's fortunes with it and putting the hotel through a series of name changes and renovations as--assuredly a draw for ghosts, who are disturbed when things do not remain the same. Over the years, the 10-story hotel has also been the scene of several deaths, whose souls may still reside within. The Hotel Lawrence's top floor is particularly rife with spirits, and perhaps not such a lucky place to stay. Resident top-floor ghosts include a woman who fell to her death--or was pushed, a congressman who committed suicide, and two men who were both murdered in Room 1009: one called Brookshire, whose throat was cut, and gambler Jack "Smiley" Jackson. Not surprisingly, crying can be heard on the 10th floor and shadows can be seen in the hallway and rooms. "Smiley" reportedly holds the door to Room 1009 shut until asked politely to move aside, and a guest in that room reported feeling as if being strangled by a towel. The eighth floor was the scene of a woman being murdered by her husband, and on the second floor, originally the site of a casino, the apparition of a sad-looking man wanders down the hall looking hopeless. High heels can be heard crossing the lobby when no one is there, laundry carts move along the halls with no one pushing them, doors open and close by themselves, cold spots are often felt, orbs of light drift through rooms, and voices are heard out of nowhere.

Lumber magnate Simon Benson commissioned the building of the Benson Hotel in 1913 as an annex to the Oregon Hotel to create the finest accommodation Portland had to offer. He thus saved the financially struggling Oregon Hotel, renamed it as the Benson Hotel, turned it to profit and sold it in 1919. But he never left. Benson can be seen descending the staircase in a formal suit and in lumberjack clothing in the dining room. He's also been spotted in meeting rooms, standing at the back of the room keeping an eye on proceedings. Benson didn't like drinking in his hotel and his upper-body apparition often roams the lobby, knocking over drinks and scowling at guests. But Benson's ghost isn't the only one at his hotel. A helpful porter once appeared to help a disabled guest and then vanished. A woman in white wanders the hallways. A woman in a turquoise dress wearing several red rings appears in the hotel lobby mirror. And on the ninth floor, a little boy once appeared at a guest's bedside and let her take his arm, which felt solid and warm, before jumping at her and making faces to scare her. He then jumped on the bottom of the bed before disappearing.

The Coral Gables Biltmore Hotel was built in 1926 as "a great hotel...which would not only serve as a hostelry to the crowds thronging to Coral Gables but also would serve as a center of sports and fashion." For awhile, the hotel was the tallest in Florida and had the largest pool in the world, attracting celebrities like Judy Garland, Babe Ruth, Franklin D. Roosevelt, European royalty and Al Capone. But World War II led to the site's conversion to an Army Air Forces Regional Hospital and the University of Miami's School of Medicine. In 1983, the City of Coral Gables fully restored the historic hotel to its former glory, attracting regular celebrity guests like Bill Clinton, along with several ghosts. Gangster Thomas "Fatty" Walsh, murdered on the Biltmore's 13th floor in 1929, may be the reason that the elevators bring people there without warning while doors open and close and lights and TVs turn on and off on that floor by themselves. A woman who jumped from a tower window also wanders the halls there, along with several of the former V.A. hospital's fatalities.