The launch of the Sputnik 1 satellite by the Soviet Union on October 4, 1957, started a Cold War technological and ideological competition with the United States known as the Space Race. The demonstration of American technological inferiority came as a profound shock to the American public. The Soviets followed up with Sputnik 2, which carried Laika, a Soviet space dog.

In April 2014, Flint changed its water source from treated Detroit Water and Sewerage Department water (sourced from Lake Huron and the Detroit River) to the Flint River. Officials failed to apply corrosion inhibitors to the water. As a result, lead from aging pipes leached into the water supply, leading to extremely elevated levels of the heavy metal neurotoxin and exposing over 100,000 residents to elevated lead levels. The city switched back to the Detroit water system on October 16, 2015.

On June 6, 1944, the Invasion of Normandy began as U.S., British, and Canadian forces set out to liberate Europe from Nazi control. It was the largest air, land, and sea operation ever undertaken, involving more than 5,000 ships, 11,000 airplanes, and 150,000 soldiers. When the dust cleared, Allied Forces had suffered almost 10,000 casualties but the German lines had been breached and the defeat of Hitler was in sight. The success of D-Day was absolutely essential to Allied victory in World War II.

Wham-O, a fledgling California toy manufacturer, soon took notice of the Australian Hula Hoop craze and began selling plastic hoops in the United States. Within four months, twenty-five million Hula Hoops had been sold!

On April 15, 2013, two homemade pressure cooker bombs detonated 14 seconds apart near the finish line of the Boston Marathon, killing 3 people and injuring hundreds of others. One suspect was run over by his brother while trying to escape in a stolen car. The other was convicted of 30 charges, including use of a weapon of mass destruction.

The shooter, John Hinckley Jr., was later found not guilty by reason of insanity. Public outcry over the verdict led to the Insanity Defense Reform Act of 1984, which altered the rules for consideration of mental illness of defendants in Federal Criminal Court proceedings in the United States.

"Deep Throat" was first introduced to the public in the February 1974 book All the President's Men by Washington Post reporters Bob Woodward and Carl Bernstein. He was a key source of information behind a series of articles that eventually led to the resignation of President Nixon, as well as to prison terms for several members of his White House staff.

Billed as "An Aquarian Experience: 3 Days of Peace and Music," the concert was expected to draw 50,000 attendees, but instead drew an estimated 500,000, most of whom crashed the concert without paying. The epic event would later be known simply as Woodstock and become synonymous with the counterculture movement of the 1960s.

When the Brooklyn Dodgers signed Jackie Robinson in 1941, it heralded the end of racial segregation in professional baseball that had relegated black players to the Negro leagues since the 1880s. During his 10-year MLB career, Robinson won the inaugural Rookie of the Year Award in 1947, was an All-Star for six consecutive seasons from 1949 through 1954, and won the National League Most Valuable Player Award in 1949--the first black player so honored. He also played in six World Series, contributing to the Dodgers' 1955 World Series championship, and was inducted into the Baseball Hall of Fame in 1962.

Rejected by all the leading schools because of her sex, Blackwell applied to Geneva Medical College where her application was accepted only after being endorsed by the current students who thought it was a joke. Through hard work and dedication, however, she earned the respect of her classmates and graduated first in her class on January 23, 1849. After running a private practice for many years, Elizabeth opened a Women's Medical College to help other women achieve the dream of becoming a doctor.