76 police officers injured including two helicopter pilots blinded by laser during anti-G20 riots in Hamburg.

Thousands of demonstrators from across Europe descended on the port city ahead of the summit, attended by Donald Trump and Theresa May.

Several hundred hard-left activists called “Black Block” have been making headlines in Hamburg for clashes with police at the G20 summit. But the name represents less of an organized group and more of a protest tactic.

As the July 7-8 summit kicked off on Friday, demonstrators clad in black clothing, hats and face masks, joined in protests blocking streets and bridges. The night prior, the masked activists hurled beer bottles at security forces and set several cars on fire.

Hamburg police identified them as members of the so-called “Black Block” – the name given to a segment of protesters within a larger demonstration who conceal their identities with dark clothing – making it harder for authorities to identify individuals and to prosecute.

The “Black Block” generally comprises hard-left activists – autonomous anarchists who want to put an end to capitalism and seemingly replace it with a libertarian system where money and the state have no power.

The “Black Block” tactics of the movement rose to prominence in the 1980s during violent protests in West Germany against nuclear power plants and squatter evacuations.
Read more: Who’s who in Hamburg’s G20 protests

The term is also a catch-all title for protesters from different groups that have a range of aims and tactics and who come together to carry out a shared aim at the protest.

Although those who are involved in a “Black Block” section are united under the color of their clothing and a singular aim, the individual beliefs within the bloc can vary widely