Vera Renczi was a Romanian serial killer during the 1920s. Before she was caught, she poisoned 2 husbands, one son, and as many as 32 lovers. When the authorities searched her home they discovered thirty-two unburied zinc-lined coffins. Each contained a male corpse in varying stages of decomposition.
Britian's first serial killer - Mary Ann Cotton. She poisoned 21 people including her own mother, children and husbands.