Nikola Tesla is one of history’s most acclaimed scientists and engineers, a prolific inventor who transformed modern society.

Tesla was also an eccentric, known particularly for his showmanship, charisma, and talent when speaking in public.

However, throughout his life he struggled with mental health problems, most notably, a debilitating form of Obsessive Compulsive Disorder. Like many people with OCD, Tesla was particularly concerned with germs, cleanliness and avoiding disease. According to Smithsonian Magazine, he obsessively washed his hands, and in his later life ensured that all his food was boiled before he would touch it.

He stated that this was due to his experience of seeing bacteria in his drinking water through a microscope in his lab, commenting, “if you would only watch for a few minutes the horrible creatures, you would never again drink a drop of unboiled or unsterilized water.”

The night owl Tesla would work in his lab throughout the night, much to the distress of his neighbours, who were often kept awake by the strange noises that emanated from his house and regularly called the police out of concern for the famous scientist.

Another one of Tesla’s particular quirks was a strange obsession with the number three. He would often engage in rituals that involved the number three, including his habit of walking three times around a building before entering it.

When dining he would fold 18 napkins before he started eating because 18 was divisible by three. When arriving at a hotel, he always requested that his room number was divisible by three and specified that he required 18 fresh towels to be delivered every morning.

In addition to boiling all of his food, he would also precisely determine the cubic mass of the food on his plate, and then calculate the precise number of jaw movements required to digest it. He had a profound phobia of round objects, and could not remain in the company of a woman who was wearing earrings!

While these strange habits may appear comical, they evidence a man struggling with serious mental illness, born at a time that did not understand his struggles.