Thousands of religious, political and self-improvement cults are active around the world, and an estimated 2 to 5 million Americans have been involved in a cult at some point. Not all cults are destructive, but members' unwavering faith in an absolute leader and an intense devotion to a cause often lay the groundwork for criminal acts to take place--even murder and mass suicides.

- The Manson Family
Hippie devotees turn violent to manifest God's race war

- The Peoples Temple
Hundreds of utopia seekers meet their end in the Guyanese jungle by ingesting a cyanide-laced drink

- The Vampire Clan
Teenagers consume blood and bludgeon an unsuspecting Florida couple to death

- Heaven's Gate
Nike-adorned disciples commit suicide to transport onto a spaceship approaching

- Earth Silvia Meraz Moreno's Santa Muerte
Cult Members collect sacrificial blood by slicing open victims' veins while their hearts are still beating