U.S. President Franklin D. Roosevelt dies in office; Vice President Harry S. Truman succeeds him. Date: April 12, 1945 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1945 📅 On This Day (Today)

The polio vaccine, developed by Dr. Jonas Salk, is declared safe and effective. Date: April 12, 1955 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1955 📅 On This Day (Today)

Space Race: The Soviet cosmonaut Yuri Gagarin becomes the first human to travel into outer space and perform the first crewed orbital flight, Vostok 1. Date: April 12, 1961 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1961 📅 On This Day (Today)

The Soviet nuclear-powered submarine K-33 collides with the Finnish merchant vessel M/S Finnclipper in the Danish straits.[citation needed] Date: April 12, 1963 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1963 📅 On This Day (Today)

Canadian runner and athlete, Terry Fox begins his Marathon of Hope Run in St. John's, NF Date: April 12, 1980 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1980 📅 On This Day (Today)

Transbrasil Flight 303, a Boeing 727, crashes on approach to Hercílio Luz International Airport in Florianópolis, Brazil. Fifty-five out of the 58 people on board are killed. Date: April 12, 1980 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1980 📅 On This Day (Today)

The first launch of a Space Shuttle (Columbia) takes place: The STS-1 mission. Date: April 12, 1981 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1981 📅 On This Day (Today)

Harold Washington is elected as the first black mayor of Chicago. Date: April 12, 1983 Read more on Wikipedia → 📅 Other events on April 12 📅 Events on this day in 1983 📅 On This Day (Today)