May: The RAND Corporation is established as an independent nonprofit policy research and analysis institution.

May 4: Laurence Olivier's film version of Hamlet makes its world premiere in London.

May 11: Luigi Einaudi becomes President of the Italian Republic.

May 14 The Declaration of Independence of Israel is made.

May 15: 1948 Arab-Israeli War: The British Mandate of Palestine is officially terminated; expeditionary forces from Egypt, Transjordan, Syria and Iraq invade Israel and clash with Israeli forces. - The murder of a 3-year-old girl in Blackburn, England leads to the fingerprinting of more than 40,000 men in the city in an attempt to find the murderer.

May 16: Chaim Weizmann is elected as the first President of Israel.

May 18: The first Legislative Yuan of the Republic of China officially convenes in Nanking.

May 22: The Soviets launched the largest Lithuanian deportation to Siberia.

May 25: The United Church of Christ in the Philippines (UCCP) was founded on this date at Ellinwood Malate Church in Manila, Philippines.

May 26: The U.S. Congress passes Public Law 557, which permanently establishes the Civil Air Patrol as the auxiliary of the United States Air Force.

May 28: Daniel Francois Malan defeats Jan Smuts and becomes Prime Minister of South Africa, ushering in the era of apartheid, which is finally dismantled by F W de Klerk in 1994.

May 30: A dike along the Columbia River breaks, obliterating Vanport, Oregon within minutes: 15 people die and tens of thousands are left homeless. (source: Wikipedia)