On December 8, 1980, a young man named Mark David Chapman asked John Lennon for his autograph in New York. Hours later, he fired four hollow-point bullets into Lennon's back — killing him almost instantly.

Catherine Howard was just a teenager when she married the middle-aged King Henry VIII in 1540 — and she was decapitated on his orders just two years later.

Ever since President Zachary Taylor died suddenly in 1850 after just 16 months in office, many have suspected foul play on the part of his political enemies.

Experts weren't sure whether to believe Hernán Cortés' reports of an Aztec temple with a wall featuring 130,000 human skulls — until a 2017 excavation revealed the chilling truth.

While Thomas Jefferson was the main author of the Declaration of Independence, the congressional committee of John Adams, Ben Franklin, Roger Sherman, and Robert Livingston played an important role.

The Underground Railroad was neither underground nor a railroad — but it did fight the system of slavery by secretly shepherding slaves to freedom in the North.

How many people did Ted Bundy kill? We may never know the full extent of Bundy's heinous crimes, but we can share the tales of the women who we know crossed his path.

The night after murdering Sharon Tate and her friends, the Manson Family stabbed Leno and Rosemary LaBianca to death.

Weighing in at 2,000 pounds and sporting arm-sized fangs, the entelodont earned its status as the "hell pig" of prehistoric North America.

Susan Atkins fell in love with Charles Manson the minute she met him in San Francisco. She loved him so much, in fact, she obeyed his orders to kill.

Patricia Krenwinkel once thought she'd become a nun. Instead, she became a part of Charles Manson's "family" and killed in his name.