1. The Boston Massacre Trials began on September 1, 1770. The trials were held in the aftermath of the Boston Massacre, in which British soldiers fired on a group of colonists, resulting in five deaths. The trials were highly politicized and became a symbol of colonial resistance to British rule.

2. On September 1, 1835, Samuel Morse demonstrated his telegraph machine for the first time. The demonstration took place in the chambers of the US Supreme Court in Washington DC, and was witnessed by a number of prominent politicians and scientists. Morse's invention revolutionized communication and paved the way for the development of modern telecommunications.

3. The first vehicle registrations in Massachusetts began on September 1, 1903. The state became the first in the country to require vehicle registration, in an effort to regulate the growing number of automobiles on the roads. The first registration fee was $2, and the state issued 3,000 registrations in the first year.

4. On September 1, 1969, the Illinois Central Railroad's City of New Orleans train derailed in Salem, Illinois. The accident killed 11 people and injured over 200, making it one of the deadliest train accidents in US history. The cause of the accident was attributed to a broken rail, and led to increased safety regulations for railroads.

5. Massachusetts passed a law raising the minimum wage to $15 on September 1, 2021. The state became the eighth in the US to raise the minimum wage to $15, following in the footsteps of California, New York, and others. The law is expected to benefit over 400,000 workers in the state and improve income inequality.