Every year on November 5th, members of the hactivist collective Anonymous get together in major cities across the globe, dust off their Guy Fawkes masks, and march through the streets in a show of force against the establishment, the phony, and the corrupt.
At least, that's the intent - the whole concept of Anonymous being diffuse and undefined, anybody can show up, from anarcho-capitalists to full-on anarchists to even the occasional Trump supporter. But the spirit is generally anti-establishment.
I've covered this protest for three years now. There's always been a certain level of anger and discontent in the air, but this is the first time it's become violent.