That was the Gettysburg address because the Gettysburg battle was very violent and hit hard toll on the north
Checks and Balances because one branch keeps the other one in check
The assembly line would be my first choice.
the US was very concerned because of the fact that Cuba had nuclear missiles within range of Washington D.C. and the leader of Cuba was being heavily supported by the Russians which at this time the US were involved in a cold war with where each side was moments from launching nuclear missiles at one another.
At the beginning of the 19th century, most Americans had no idea what lay beyond The Mississippi River.
