- Feb 1 Space Shuttle Columbia disintegrates during reentry into the Earth's atmosphere, killing all seven astronauts aboard.
- Feb 15 An estimated 6-11 million people around the world take to the streets to protest against war with Iraq
- Mar 13 The journal Nature reports that 350,000-year-old footprints of an upright-walking human have been found in Italy
- Mar 19 Airstrikes by an American and British-led coalition signal the beginning of the invasion of Iraq, without United Nations support and in defiance of world opinion
- Apr 9 Baghdad falls to U.S. forces, ending the invasion of Iraq, but resulting in widespread looting
- Apr 14 The Human Genome Project is completed with 99% of the human genome sequenced to an accuracy of 99.99%
- Apr 16 Treaty of Accession is signed in Athens admitting 10 new member states to the European Union
- Jun 10 The Spirit Rover is launched, beginning NASA's Mars Exploration Rover mission
- Aug 11 NATO takes over command of the peacekeeping force in Afghanistan, marking its first major operation outside Europe in its 54-year-history.
- Dec 13 Former Iraqi President Saddam Hussein is captured near his home town of Tikrit, during Operation Red Dawn by US forces
- Apr 28 Andre Agassi recaptures the world no. 1 ranking to become the oldest top-ranked male in the history of the ATP rankings (33 years, 13 days)
- May 22 In Fort Worth, Texas, Annika Sörenstam becomes the first woman to play the PGA Tour in 58 years.
- Jun 23 Barry Bonds steals second base against the LA Dodgers, becoming the first player in MLB history to have 500 career homers and 500 steals
- Nov 16 Lionel Messi makes his official debut for FC Barcelona in a friendly against Porto
The last 'old style' Volkswagen Beetle rolls off the assembly line in Mexico
On July 30, 2003