CNN  — 

Hong Kong is facing a major political crisis amid repeated street protests and mass demonstrations. What started as a movement against a controversial law has expanded into something much bigger.

Over the past few months, the demonstrations have evolved from millions marching through the streets, to groups of protesters in hard hats storming government headquarters and shutting down the city’s international airport for two days. While the majority of protesters have been peaceful, frustration is building on all sides.

Protesters are now demanding greater democracy and an inquiry into alleged police brutality during past demonstrations. Hong Kong’s billionaires are calling for order. And as unrest intensifies, Beijing’s tone is becoming increasingly heated.

Here’s what you need to know:

What’s the history here?

Hong Kong belongs to China, but it has its own currency, political system and cultural identity. Many Hong Kong residents don’t see themselves as Chinese, but rather as Hong Kongers.

That difference goes back generations; the city was a colony and territory of the United Kingdom for more than 150 years, until the British handed it back over to China in 1997. Today, Hong Kong’s legal system still mirrors the British model, prizing transparency and due process.

A policy dubbed “one country, two systems,” enshrines this uniqueness. Under the policy, Hong Kong’s maintains a de-facto constitution, known as the Hong Kong Basic Law. It guarantees freedoms that are unavailable to Chinese mainlanders, such as the right to protest, the right to a free press and freedom of speech.

One of the tenets in the Basic Law is that Hong Kong has the right to develop its own democracy, and previous Chinese officials pledged that the central government in Beijing wouldn’t interfere with that. But in recent years, Beijing has repeatedly reinterpreted the Basic Law – now it says it has “complete jurisdiction” over Hong Kong.

The Basic Law states that Hong Kong “shall safeguard the rights and freedoms of the residents” for 50 years after the handover. But many residents say mainland China is already starting to encroach on those rights.

This perceived threat to Hong Kong’s rule of law has led to the regular confrontations which has seen hundreds of protesters arrested so far.

Protesters stormed and partially sacked Hong Kong's legislature.

What are the protesters demands?

Hong Kong’s summer of protest has seen all kinds: Massive peaceful marches; widespread strikes from different professional industries; and smaller group actions that have ended with clashes and vandalism, including putting up a banner in the seat of government that read “There’s no rioters, there’s only tyranny.”

In early August, violent outbreaks at Hong Kong airport set a newly combative tone, with protesters attacking and temporarily detaining two people.

Protests began in March, but they kicked off in earnest in June. They were sparked by widespread opposition to a now-shelved extradition bill, but have since expanded to demands for full democracy and police accountability.