Christopher Columbus's arrival in the Americas is recorded as having taken place on October 12, 1492, yet every year it is celebrated on the second Monday of October.
Christopher Columbus set sail for India in august 1492, at a time when European scholars weren't aware of the existence of the Pacific Ocean, history.com reports. The Italian-born explorer had the support of Spanish monarchs King Ferdinand and Queen Isabella.
He first set foot in Cuba, which he believed was China, and historians regard him as the first European to find the Americas. Along with the surviving 39 of his men, after what was a grueling 2-month journey, he put in place the first Spanish colony in the newfound continent, which he named The New World.
The men were severely ill and were carrying the smallpox and influenza viruses, which they passed on to the indigenous people they believed were Indians. The illness spread and birthed outbreaks that decimated the Native Americans in the area.
Before his death in 1506, Columbus took three other ships across the Atlantic, and only realized he had not, in fact, reached India, the third time around.
Columbus Day became an official national holiday in the United States in 1937, after first being observed in 1792, by the New York Columbian Order, or Tammany Hall, 300 years after his arrival in America.
Patriotic festivities were first organized nation-wide 100 years later, in 1892, when president Benjamin Harrison proclaimed the day should be commemorated as a great historical event for the States.
"On that day let the people, so far as possible, cease from toil and devote themselves to such exercises as may best express honor to the discoverer and their appreciation of the great achievements of the four completed centuries of American life," president Harrison stated, in support for the ceremonies.
Columbus Day was later deemed a national holiday by President Franklin D. Roosevelt, after political pressure from Catholic organization Knights of Columbus. Although originally set for October 12, it started being celebrated on the second Monday in October in 1971.
Via: The History Behind Columbus Day