In History, Today on October 4

The Gregorian calendar was adopted by Pope Gregory XIII, replacing the Julian calendar. This day was followed by October 15, 1582, in countries that adopted the new calendar immediately.

Mexico adopted a new constitution and became a federal republic, officially known as the United Mexican States.

The Kingdom of Belgium was established after the Belgian Revolution, which led to its independence from the Netherlands.

The Orient Express made its inaugural journey from Paris to Istanbul, marking the beginning of a new era in luxury train travel.

The Soviet Union launched Sputnik 1, the first artificial Earth satellite, marking the start of the space age and the U.S.-Soviet space race.

Pope Paul VI became the first pope to visit the United States, addressing the United Nations General Assembly in New York City.

Russian President Boris Yeltsin ordered the storming of the Russian parliament building, ending a constitutional crisis and a standoff with hardline lawmakers.

SpaceShipOne wins the Ansari X Prize by becoming the first privately built spacecraft to fly to space twice within two weeks.

WikiLeaks is launched, aiming to publish news leaks and classified media provided by anonymous sources.

Apple Inc. announces the iPhone 4S, featuring the introduction of Siri, a voice-activated personal assistant.

Hurricane Matthew makes landfall in Haiti as a Category 4 hurricane, causing widespread devastation and loss of life.

The Nobel Prize in Chemistry is awarded to Jacques Dubochet, Joachim Frank, and Richard Henderson for developing cryo-electron microscopy.