Important events of 1990 include the Reunification of Germany and the unification of Yemen, the formal beginning of the Human Genome Project, the launch of the Hubble Space Telescope, the separation of Namibia from South Africa, and the Baltic states declaring independence from the Soviet Union amidst Perestroika. Yugoslavia's communist regime collapses amidst increasing internal tensions and multiparty elections held within its constituent republics result in separatist governments being elected in most of the republics marking the beginning of the breakup of Yugoslavia. Also in this year began the crisis that would lead to the Gulf War in 1991 following the Iraq invasion and the largely internationally unrecognized annexation of Kuwait. This annexation resulted in a crisis in the Persian Gulf involving the issue of the sovereignty of Kuwait and fears by Saudi Arabia over Iraqi aggression against their oil fields near Kuwait. This led to Operation Desert Shield being enacted with an international coalition of military forces being built up on the Kuwaiti-Saudi border with demands for Iraq to peacefully withdraw from Kuwait. Also in this year, Nelson Mandela was released from prison, and Margaret Thatcher resigned as Prime Minister of the United Kingdom after more than 11 years.
1990 was an important year in the Internet's early history. In the fall of 1990, Tim Berners-Lee created the first web server and the foundation for the World Wide Web. Test operations began around December 20 and it was released outside CERN the following year. 1990 also saw the official decommissioning of the ARPANET, a forerunner of the Internet system and the introduction of the first content web search engine, Archie, on September 10.
September 14, 1990 saw the first case of successful somatic gene therapy on a patient.
Due to the early 1990s recession that began that year and uncertainty due to the collapse of the socialist governments in Eastern Europe, birth rates in many countries stopped rising or fell steeply in 1990. In most western countries the Echo Boom peaked in 1990; fertility rates declined thereafter.
Encyclopædia Britannica, which ceased printing in 2012, saw its highest all time sales in 1990; 120,000 volumes were sold that year. The number of librarians in the United States also peaked around 1990.



: The Pisa tower closed.
: Trial relating to Exxon Valdez.