May 18

Crusader mobs massacre hundreds of Jewish residents of Worms, Germany, in one of the deadliest attacks of the early Crusades.

A mob of Crusaders and local townspeople massacred hundreds of Jewish residents of Worms, Germany, part of a broader wave of violent, unauthorized attacks against Jewish communities across the Rhineland that accompanied the popular, disorganized beginning of the First Crusade, despite official Church teaching prohibiting such violence.

Henry II of England marries Eleanor of Aquitaine, a union that dramatically expanded Angevin territorial holdings in France.

Henry II of England married the recently divorced and enormously wealthy Eleanor of Aquitaine just weeks after her marriage to King Louis VII of France was annulled, and her vast inherited territories in southwestern France, combined with Henry's own holdings, created the sprawling Angevin Empire that dominated much of western Europe for the following decades.

The Great Siege of Malta begins as Ottoman forces attempt to seize the strategically vital island from the Knights Hospitaller.

Ottoman forces under Sultan Suleiman the Magnificent launched a massive assault intended to seize the strategically vital island of Malta from the Knights Hospitaller in what became known as the Great Siege of Malta, a grueling four-month campaign that ultimately ended in a decisive and celebrated defensive victory for the vastly outnumbered knights.

Napoleon Bonaparte is proclaimed Emperor of the French by the French Senate.

The French Senate formally proclaimed Napoleon Bonaparte Emperor of the French, ratified soon after by a national plebiscite, completing his transformation from ambitious revolutionary general to hereditary monarch, a title he held until his ultimate military defeat and second, final exile a decade later.

Union forces under Ulysses S. Grant begin the Siege of Vicksburg, a pivotal Civil War campaign for control of the Mississippi River.

Union General Ulysses S. Grant began the extended Siege of Vicksburg after his army's assaults on the well-defended city failed, launching a lengthy Mississippi River campaign whose eventual Confederate surrender split the Confederacy in two along the river and gave Union forces complete control of the strategically vital waterway.

The U.S. Supreme Court rules in "Plessy v. Ferguson" that racial segregation under a "separate but equal" doctrine is constitutional.

The U.S. Supreme Court ruled in "Plessy v. Ferguson" that racially segregated public facilities were constitutional under a "separate but equal" legal doctrine, a decision that entrenched Jim Crow segregation laws across the American South for nearly six decades until it was finally and unanimously overturned by "Brown v. Board of Education."

Jacqueline Cochran becomes the first woman to break the sound barrier, piloting a jet over California.

Aviator Jacqueline Cochran became the first woman to break the sound barrier, piloting a borrowed Canadair Sabre jet over Rogers Dry Lake in California with test pilot Chuck Yeager flying alongside as a chase pilot, an achievement that further advanced her already pioneering, record-setting career in American aviation.

India conducts its first successful nuclear weapons test, code-named Smiling Buddha.

India successfully detonated its first nuclear device in an underground test in the Rajasthan desert codenamed Smiling Buddha, deliberately timed to coincide with Buddha Purnima, making it the sixth country to demonstrate confirmed nuclear weapons capability and significantly altering the strategic military balance in South Asia.

Mount St. Helens erupts catastrophically in Washington state, killing 57 people and causing widespread destruction.

Mount St. Helens in Washington state erupted catastrophically following weeks of escalating seismic activity and a bulging north flank, triggering the largest volcanic landslide in recorded history and a powerful lateral blast that killed 57 people while flattening and devastating hundreds of square miles of surrounding forest.

A school shooting at Santa Fe High School in Texas kills ten people.

A gunman opened fire at Santa Fe High School in Texas, killing ten people, mostly students, in one of a distressingly long series of American school shootings during the decade that intensified national political debate over gun control legislation, school security measures, and mental health resources.