Between 1948 and 1975, the U.S. Army tested chemical weapons like mustard gas and LSD on American soldiers at Maryland's Edgewood Arsenal facility.

The mistake wasn't uncovered until nearly 50 years later when the now-adult Paul Fronczak decided to take a DNA test and discovered he wasn't related to his mom or dad.

Martha Place brutally murdered her 17-year-old stepdaughter Ida with acid in 1898 and was executed by electric chair the following year.

Between 1979 and 1981, David Carpenter murdered so many people along Bay Area nature trails that some parks posted ominous "Do Not Hike Alone" warning signs.

An Oregon family of five vanished days before Christmas. Was it an accident or murder?

Catherine Parr was the last of King Henry VIII's six wives and the only one to neither be cast aside nor killed by the volatile English monarch.

During World War I, German saboteurs ignited 2 million pounds of munitions on Black Tom Island in New York Harbor, triggering one of the largest explosions to ever occur on American soil.

Less than half of the racers in the 1904 Olympic marathon finished the notoriously perilous race — and only after the winner was dragged across the finish line.

After meeting Adolf Hitler when she was 17 years old, Eva Braun became the Nazi dictator's long-time mistress before marrying him on April 29, 1945.

In 1806, well-respected farmer James Purrington suddenly decided to murder his wife and seven of his children, leaving his neighbors in small-town Maine shocked and horrified.

In July 1949, Norma Padgett accused four Black men of sexually assaulting her and violent mobs quickly formed to bring her attackers to justice — destroying the lives of four innocent men.