We’re all excited to have a public holiday every July 1, but you should also know the story behind it. July 1 is Establishment Day — marking the anniversary of the the 1997 Handover, when Britain transferred its sovereignty back to China after 156 years of ruling the territory.

Every year, the Hong Kong government puts on a series of celebrations throughout the day, capped off with fireworks in the evening. But the event that usually draws attention from around the world is the July 1 rally, which takes place in Hong Kong every year.

While the peaceful demonstration has taken place annually since 1997, it didn’t gain momentum until 2003, when Hongkongers came out in droves to protest the controversial Basic Law Article 23. The proposed legislation pledged national security laws, including the prohibition of “any act of treason, secession, sedition, subversion against the Central People’s Government.” It also attempted to ban political organizations from associating with foreign equivalents.

Organized by pan-democratic Civil Human Rights Front, the 2003 rally came at a time of serious political unrest in Hong Kong and drew around half a million protesters. In the end, the rally worked and Article 23 was shelved.

Since then, the July 1 protest has become an important event for pro-democracy activists in the city. Although there are different focuses each year, the protests usually center around fighting for democracy, universal suffrage, and freedom of speech in Hong Kong.