In 1835 Maria Monk claimed that Montreal's Hôtel-Dieu convent was a vice den. She was making it all up... but Americans desperately wanted to believe her.
In August 1834 Bostonians burned down a convent full of nuns, thanks to religious prejudice and the suspicious testimony of a lazy teenager with a grudge.
In October 1846, the world discovered surgical anesthesia. Four men would spend the next two decades fighting over which one of them deserved the credit.
The idea that color has healing power is a relatively modern (and utterly fallacious) one. We discuss its development through the 19th and 20th centuries.