1. On July 20, 1875, the infamous outlaw Henry Plummer was hanged in Bannack, Montana. Plummer was the leader of a gang of road agents known as the "Innocents," who terrorized gold-mining towns in Montana during the mid-1800s.

2. In 1917, the town of Butte, Montana experienced a devastating fire on July 20. The fire started in a warehouse and quickly spread to nearby buildings, destroying more than 2000 homes and businesses.

3. On July 20, 1931, the Montana State Prison at Deer Lodge experienced its deadliest riot in history. The riot was sparked by prisoners protesting working conditions and lack of pay. When the riot was over, six prisoners and one guard were dead.

4. In 1969, the Apollo 11 mission successfully landed on the moon on July 20. Montana residents were among the millions of people worldwide who watched the historic event on television.

5. On July 20, 1985, the Unabomber (Ted Kaczynski) detonated a bomb at a computer store in Sacramento, California that injured several people. Kaczynski, who had lived as a recluse in Montana for many years, was eventually apprehended by authorities and sentenced to life in prison.