Mario as Nintendo's mascot finds a rival in Sega's Sonic the Hedgehog with the release of Sonic the Hedgehog on the Sega Mega Drive/Genesis in 1991. Sonic the Hedgehog would go on to become one of the most successful video game franchises of the decade and of all time. Los Angeles riots – resulted in 53 deaths and 5,500 property fires in a 100-square-mile (260km 2) riot zone. The riots were a result of the state court acquittal of three white and one Hispanic L.A. police officer by an all-white jury in a police brutality case involving motorist Rodney King. In 1993, all four officers were convicted in a federal civil rights case.

Armenia – the Armenian SSR became the Republic of Armenia following the Declaration of Independence of Armenia. Eurostar logo 1994–2011 A pair of Eurostar trains at the former Waterloo International since moved to St Pancras International Israeli military forces withdrew from these Palestinian territories in compliance with the accord, which marked the end of the First Intifada (a period of violence between Palestinian Arab militants and Israeli armed forces from 1987 to 1993). The resignation of President Boris Yeltsin on 31 December 1999 resulted in Prime Minister Vladimir Putin's succession to the position.

April 26, 1994: China Airlines Flight 140, an Airbus A300, crashed just as it was about to land at Nagoya Airfield, Japan, killing 264 and leaving only seven survivors.

In December 1999, torrential rains and flash floods killed tens of thousands of Venezuelans living in the state of Vargas in a natural disaster known as the Vargas tragedy. The 1990s represented continuing social liberalization in most countries, coupled with an increase in the influence of capitalism, which would continue until the Great Recession of the late 2000s/early 2010s. Canadian politics was radically altered in the 1993 federal election with the collapse of the Progressive Conservative Party of Canada. A major political party in Canada since 1867, the party went from controlling the government to being left with only two seats. The New Democratic Party collapsed as well, with their sets declining from 44 to 9. The Liberal Party of Canada was the only genuinely 'national' political party left standing. Regionally-based parties, such as the Quebec-based Bloc Québécois and the almost entirely Western Canada-based Reform Party of Canada, rose from political insignificance to being major political parties.Dissolution of Czechoslovakia (1993) – the Slovak Republic adopts the Declaration of Independence from the Czech and Slovak Federative Republic ( Czechoslovakia).

South Korea and Taiwan became developed countries, and two of the Four Asian Tigers in the 1990s. Following democratic reforms in 1988, neoliberal policies were implemented by President Kim Young-sam (South Korea) and President Lee Teng-hui (Taiwan), both who led their countries during the 1997 Asian financial crisis. The Troubles in Northern Ireland (1998) involved 30 years of conflict that ended on 10 April 1998, when the Good Friday Agreement was signed. Gulf War oil spill: Resulting from actions taken during the Gulf War in 1991 by the Iraq military, the oil spill caused considerable damage to wildlife in the Persian Gulf, especially in areas surrounding Kuwait and Iraq. On 6 August 1991, CERN, a pan-European organization for particle research, publicized the new World Wide Web project. [43] Although the basic applications and guidelines that make the Internet possible had existed for almost two decades, the network did not gain a public face until the 1990s.Protease inhibitors introduced, allowing HAART therapy against HIV; drastically reduces AIDS mortality. The 1990s (pronounced "nineteen-nineties", shortened to " the '90s" and often referred to as simply " the Nineties") was a decade that began on January 1, 1990, and ended on December 31, 1999.