On this date in history:

In 1861, the Civil War began when Confederate troops opened fire on Fort Sumter in South Carolina.

In 1935, Your Hit Parade premiered on radio.

In 1945, Franklin Delano Roosevelt, the longest-serving president in U.S. history, died of a cerebral hemorrhage at Warm Springs, Ga., three months into his fourth term. About 3 hours later, Vice President Harry S. Truman was sworn in as chief executive.

In 1955, U.S. health officials announced that the polio vaccine developed by Dr. Jonas Salk was safe, potent and effective.

In 1961, Soviet cosmonaut Yuri Gagarin, in Vostok 1, became the first human to travel to outer space and the first to orbit Earth.

In 1981, the Columbia was launched on the first U.S. space shuttle flight.

In 2002, Venezuelan President Hugo Chavez was overthrown in a military coup. (He was returned to office two days later riding a wave of public sentiment.)

In 2003, Gen. Amir al-Saadi, Saddam Hussein's top science adviser, denied Iraq had any weapons of mass destruction and surrendered to U.S. forces.

In 2007, Kurt Vonnegut Jr., whose novels such as Slaughterhouse-Five resonated with a generation, died in New York at the age of 84.

In 2009, U.S. Navy SEALs rescued an American ship captain, Richard Phillips, held hostage by pirates off the Somalia coast, by killing three of the kidnappers four days after the standoff began.

In 2012, North Korea, defying international warnings, fired a long-range test rocket but the launch ended in failure. U.S. officials said the rocket broke up and fell into the sea.

In 2013, John Berry ended a four-year term as director of the U.S. Office of Personnel Management.

In 2014, pro-Russian gunmen seized some police stations and other facilities in an escalating crisis in eastern Ukraine.

Copyright 2015 by United Press International