May 1: Arturo Frondizi becomes President of Argentina. - The Nordic Passport Union comes into force.
May 9: Actor-singer Paul Robeson, whose passport has been reinstated, sings in a sold-out one-man recital at Carnegie Hall. The recital is such a success that Robeson gives another one at Carnegie Hall a few days later; but, after this, Robeson is seldom seen in public in the United States again. His Carnegie Hall concerts are later released on records and on CD.
May 10: Interviewed in the Chave d'Ouro café, when asked about his rival António de Oliveira Salazar, Humberto Delgado utters one of the most famous comments in Portuguese political history: "Obviamente, demito-o! (Obviously, I'll sack him!)".
May 12: A formal North American Aerospace Defense Command agreement is signed between the United States and Canada.
May 13: French Algerian protesters seize government offices in Algiers, leading to a military coup. - During a visit to Caracas, Venezuela, Vice President Richard M. Nixon's car is attacked by anti-American demonstrators.
May 15: The Soviet Union launches Sputnik 3. - MGM's Gigi opens in New York City, beginning its run in the U.S. after being shown at the Cannes film festival. The last of the great MGM musicals, it will become a huge critical and box office success and win nine Academy Awards including Best Picture. Gigi is Lerner and Loewe's first musical written especially for film, and is deliberately written in a style evoking the team's My Fair Lady, which was still playing on Broadway at the time and could not be filmed yet.
May 18: An F-104 Starfighter sets a world speed record of 1,404.19 mph (2,259.82 km/h).
May 20: Fulgencio Batista's government launches a counteroffensive against Castro's rebels.
May 21: United Kingdom Postmaster General Ernest Marples announces that from December, Subscriber Trunk Dialling will be introduced in the Bristol area.
May 23: Explorer 1 ceases transmission.
May 30: The bodies of unidentified United States soldiers killed in action during World War II and the Korean War are buried at the Tomb of the Unknowns in Arlington National Cemetery. (source: Wikipedia)