The East India Tea Company Act was passed allowing British tea to be sold at a very low prices plus tax. The colonies didn't think it was right to be taxed, so they didn't buy the tea. The British men wouldn't send the tea back, so it sat in Boston Harbor unloaded. The Sons of Liberty decided to get rid of the unwanted tea. On the night of December the 16th 1773, the Son's of Liberty went aboard the ship dressed as Mohawk Indians and threw all the tea into Boston Harbor.
Picture Source: Getty