Outlaw motorcycle gangs have been a thorn in the side of US law enforcement since the 1960s. Today, these dangerous organizations are engaged in criminal activities on both coasts and throughout the American heartland. “One-percenter” motorcycle clubs – so named because the American Motorcyclist Association has said that 99% of motorcyclists are law-abiding – run drugs across the borders and participate in a litany of additional crimes, from contract killing to petty theft.

Despite their prominent role in the American underworld, outlaw bikers have long been mythologized in film, TV, and literature. Hunter S. Thompson’s book Hell’s Angels brought the gangs’ ruthless behaviour to light, and the popular TV show Sons of Anarchy rekindled America’s interest.

In the last five years, two major events reminded us that outlaw biker culture is not for the faint of heart. In 2015, nine people were killed and 18 were injured in a wild gun battle involving hundreds of bikers at the Twin Peaks restaurant in Waco, Texas. The next year, a guns-and-knives brawl involving dozens of bikers left one dead and seven injured at the National Western Complex in Denver.

Learn who’s behind these events with our list of the Most Dangerous Motorcycle Gangs in America.

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