1) Apollo 13 launched on April 11, 1970 on a mission to explore the moon but had to abort the lunar landing after an oxygen tank exploded, endangering the lives of the astronauts. 2) The fall of Saigon on April 30, 1975 marked the end of the Vietnam War as North Vietnamese forces captured South Vietnam's capital. 3) In 1979, the Soviet Union invaded Afghanistan in an attempt to prop up Afghanistan's communist government, but faced years of bloody conflict against mujahideen resistance groups like the Taliban and al Qaeda.