On This Day - April 12, 2026

The American Civil War began when Confederate forces opened fire on Fort Sumter, South Carolina. It would be known by various names, including the War Between the States, War of Northern Aggression, War of the Rebellion, Great Rebellion, War for Southern Independence, and Freedom War. Four years later it would end on April 9, 1865, after dividing the country and 620,000 soldiers died.

Charlie Chaplin's The Tramp released in the United States

The Mount Washington Observatory records winds at 231 miles per hour.

Epidemiologist and virologist Dr. Thomas Francis Jr. announced that the polio vaccine developed by Dr. Jonas Salk was up to 90% effective in preventing paralytic polio. Dr. Francis, the director of the Poliomyelitis Vaccine Evaluation Center at the University of Michigan School of Public Health, made the announcement in Ann Arbor, Michigan with Dr. Jonas Salk.

Aboard the Vostok 1, Yuri Gagarin becomes the first human in space. He orbited the Earth once before re-entering the Earth's atmosphere. Gagarin then ejected from Vostok 1 and parachuted to the ground separately from the spacecraft.