31st January 1865: Thirteenth Amendment passed by the US Congress to formally abolish slavery

It was sent to the states for ratification the next day, a process that was concluded on 6 December after the necessary three-quarters of states approved it.

4th October 1927: Work begins on the USA’s Mount Rushmore National Memorial in South Dakota

Washington’s face was the first to be completed, seven years after work began. In July 1939 Roosevelt was the final likeness to be dedicated.

5th August 1861: Abraham Lincoln signs US income tax into law to help pay for the American Civil War

The Revenue Act of 1861 was signed into law by Abraham Lincoln, imposing U.S. federal income tax for the first time.

6th November 1860: Abraham Lincoln elected as the 16th President of the USA

Abraham Lincoln was elected barely five months before the outbreak of the American Civil War, and was assassinated less than a month before its end.