High Violent Crime Rates Persis in Most Dangerous US Cities. According to BBC Science Focus Magazine, in the United States some cities grapple with high levels of violent crime despite nationwide trends showing a decrease in such incidents. Using data from the FBI we’ve identified the most dangerous cities based on serious felonies per 100,000 Americans annually. These crimes encompass murder, manslaughter, assault and robbery. While efforts like real-time crime maps and advanced technologies aim to enhance safety these cities continue to face significant challenges in curbing violence.