13. Great Enlightened Society Of Oculists

What Is It:
The Great Enlightened Society of Oculists was so secret that no one cracked their clandestine code for 250 years. The group dates back to at least 1764, and it devoted itself to secret ways of seeing knowledge. And they also performed eye surgery.

Famous Members:

Literally a bunch of 18th-century eye doctors
Why You Should Join:
The initiation ritual starts with trying to read a blank page and ends with an amulet-wearing master ripping out your eyebrow hairs. Seriously, that’s what was in the coded manuscript. Plus, if they kept their manuscript’s contents a secret for almost 300 years, they’re obviously really good at being secret.