Crime isn't something most cities brag about. But a number of America's major metro areas have a history of headline-grabbing criminal activity that undeniably attracts the interest and curiosity of visitors.

There's something about murder, mayhem, scandal and corruption that tempts the psyche of those interested in exploring the darker side of human nature. True-crime television dramas such as "Cops," "Cold Case" and "CSI" have only served to enhance the appeal.

We've done some sleuthing to identify tours in nine cities that take visitors behind the scenes and into the shadows to expose some of the most heinous crimes and savage criminals in the nation's history. Mind you, these tours are not for the squeamish.

1. True Crime Tour, New Orleans

In his song "Basin Street Blues," Louie Armstrong called New Orleans a "Land of Dreams." But deadly, terrifying crimes have been almost as common here as gumbo and jazz. Cold-hearted assassinations, murderous crimes of passion, mafia misdeeds and the unsolved trail of grisly killings by "The Axeman" all play a role in the dark side of New Orleans history.

Join your expert guide outside the Voodoo Lounge in the historic French Quarter and set out to learn about the city's violent past on this exciting, unsettling two-hour tour.

www.frenchquarterphantoms.com/true-crime-tour

2. The Helter Skelter Tour, Los Angeles

This tour sprang from the public's fascination with Charles Manson and the seven high-profile murders that rocked Los Angeles in 1969. Although widely despised, Manson was a part of the pop culture of the '60s just like The Beach Boys, Mama Cass and the Beatles.

Scott Michaels, owner of Dearly Departed Tours, has organized and scripted a revealing and fascinating three-and-a-half-hour tour that chronicles the Manson family murders. With group sizes limited to a dozen guests, this van tour visits sites relevant to the Manson family and their crimes, while featuring multimedia clips and music from the era.

www.dearlydepartedtours.com

3. Criminals, Mobsters & Gangsters, Chicago

Explore Chicago's notorious gangster past on this expertly narrated coach tour offered by Chicago Crime Tours. Lasting nearly two hours, the tour includes several photo stops.

You'll stake out some of the Windy City's most storied crime scenes including Holy Name Cathedral, Biography Theater, the Clark Street Bridge and the site of the bloody St. Valentine's Day Massacre. Even more revealing, you'll get the inside story on such famous mobsters as John Dillinger, Hymie Weiss, Al Capone, Bugs Moran and "Terrible" Tommy O'Conner.

www.chicagocrimetours.com

4. The Saint Paul Gangster Tour, St. Paul

The list of gangsters who once hung out in St. Paul reads like "America's Most Wanted" of the 1930s. A ruthless bunch, they included John Dillinger, "Baby Face" Nelson, "Ma" Barker and Alvin "Creepy" Karpis.

Visitors with a fascination for the city's seamier side will want to join this two-hour coach tour to view the sites of nightclubs, kidnappings and gun battles associated with these thugs as they carried out some of the most notorious crimes ever perpetrated in the upper Midwest.

www.wabashastreetcaves.com

5. The Lincoln Assassination Tour, Washington, D.C.

Put your headphones on and travel back in time on this suspenseful walking tour to the night of April 14, 1865, when John Wilkes Booth assassinated President Abraham Lincoln. There was a major conspiracy behind the plot to murder Lincoln, and you'll learn the key characters and their motives — and the details as to what exactly happened on that fateful night.

See it and hear it all, as one of the greatest crimes in American history plays out, complete with music and sound effects. Developed by DCWalkabout, this dynamic 90-minute tour is available 24/7 on iTunes, Amazon and Google Play and on every type of phone and tablet.

www.dcwalkabout.com

6. New York Mafia Tour, New York

Here's a free, self-guided walking tour that takes you through the heart of Little Italy to the East Village, calling out the most famous mob locations along the way. The tour pinpoints exact locations where "hits" took place and identifies bars, restaurants and "social clubs" favored by mobsters from the big five Mafia families names like Genovese, Gambino, Gotti, Gallo and Luciano.

Follow up your walking tour with a visit to the Museum of the American Gangster at 80 St. Marks Place in the East Village, featuring a small but noteworthy collection of mob memorabilia.

www.freetoursbyfoot.com/new-york-mafia-tour

7. Kansas City Gangster Tour, Kansas City

Currently available on Saturdays only, this 90-minute interactive coach tour highlights an infamous period in Kansas City’s history the Pendergast era from 1920 to 1945. Aided by historical films and photos, tour members learn and see how "Boss Tom" Pendergast controlled the political system and the very fabric of life in the city.

The tour gets underway at Union Station, where bullet holes from the violent 1933 Kansas City Massacre can still be seen, and it moves on to point out where speakeasies and gambling halls once thrived as well as the one-time homes and workplaces of crime bosses.

www.kctg.com/tour/group-gangster

8. Boston Crime Tour, Boston

Authoritative and extremely popular, this tour was meticulously researched and created by Boston natives who grew up in the very neighborhoods where James "Whitey" Bulger and his Winter Hill gang of Irish mobsters ran amuck by keeping authorities, including the FBI, on their payroll.

Learn the true story on Bulger and see firsthand where some of Boston's most legendary crimes took place, dating back to the 18th century when pirates pillaged merchant vessels right in the city's harbor. The tour also delves into the 1950 Brink's armored car heist, pulled off by nine masked bandits in downtown Boston, and the still controversial Boston Strangler murders of the 1960s.

www.crimetourboston.com

9. The Mob Museum, Las Vegas

Not a tour per se, but nonetheless an opportunity to gain an authentic view of organized crime's substantial impact on Las Vegas history, the Mob Museum properly known as the Las Vegas Museum of Organized Crime & Law Enforcement is well worth a visit.

Housed in a one-time federal courthouse and the brainchild of former Las Vegas mayor and mob defense attorney Oscar Goodman, this museum presents the real stories and actual events of mob history in Vegas via a wide range of interactive exhibits.

www.themobmuseum.org