In the 1760's Britain was deep in debt and decided to tax the American Colonists to pay off those debts.

They thought it was fair to tax the colonists because of all the wars they had helped them fight, but the colonists disagreed because they didn't have any say in parliament.

Britain decided to remove all taxes except for the tax on tea. The colonists decided to boycott and bring in Dutch tea, which left the British East India Company with extra tea and facing bankruptcy.

A group of men called the Sons of Liberty formed to protest taxes from Britain. They held a meeting and decided to no longer accept taxes on tea or allow tea to be unloaded in the docks.

Governor Thomas Hutchinson refused to allow the ships to return to Britain and demanded the tea be unloaded, but never offered a reasonable compromise. 

That same night on December 16, 1773 a group of men, mainly composed of the Sons of Liberty, disguised themselves as Native Americans and snuck on the ship.

They threw around 342 chests of tea into the water that night. No property was damaged, but their voices were heard.