13. Abraham Lincoln
Source: Wikipedia.
Abraham Lincoln became the country’s 16th president in 1861, shortly before the outbreak of the American Civil War.
The son of a Kentucky frontiersman, Lincoln worked on a farm and split rails for fences while teaching himself to read and write. He had an IQ of 148, according to Simonton’s estimates, and was the only president to have a patent after inventing a device to free steamboats that ran aground. He is best remembered for keeping the Union intact during the Civil War, and for his 1863 signing of the Emancipation Proclamation that forever freed slaves within the Confederacy.