History

Anonymous is the most famous ‘hacktivist’ group in the world. Anonymous is a decentralized international activist and hacktivist collective, and a movement primarily known for its various cyberattacks against international corporations and several governments institutions worldwide.

This group originated in 2003 when a few random users came together to talk about anarchy, oppression, and the state of things on 4Chan image boards. The New Yorker summarizes that they might be the most powerful non-government hacking group in the world.

Mask

The mask you see worn at Anonymous is called a Guy Fawkes mask, so named for a seventeenth-century Briton who infamously attempted to bomb the House of Lords. He was planning to kill King James I, so that his Catholic daughter could ascend to the throne.