Lockheed L-1011 TriStar enters service with Eastern Airlines. April 27 The Burundian Genocide against the Hutu begins; more than 500,000 Hutus die. A no-confidence vote against German Chancellor Willy Brandt fails under obscure circumstances. April 29 – The fourth anniversary of the Broadway musical Hair is celebrated with a free concert at a Central Park bandshell, followed by dinner at the Four Seasons. There, 13 Black Panther protesters and the show's co-author, Jim Rado, are arrested for disturbing the peace and for using marijuana. May May 2 – Fire at the Sunshine Mine, a silver mine in Idaho, kills 91. May 5 – An Alitalia DC-8 crashes west of Palermo, Sicily; 115 die. May 7 – General elections are held in Italy. May 10 – Operation Linebacker and Operation Custom Tailor begin with large-scale bombing operations against North Vietnam by tactical fighter aircraft. May 13 – A fire in a nightclub atop the Sennichi department store in Osaka, Japan, kills 115. May 21 – In St. Peter's Basilica (Vatican City), Laszlo Toth attacks Michelangelo's Pietà statue with a geologist's hammer, shouting that he is Jesus Christ. May 22 The Dominion of Ceylon becomes the republic of Sri Lanka under prime minister Sirimavo Bandaranaike, when its new constitution is ratified. Ferit Melen forms the new (interim) government of Turkey (35th government) May 23 – The Tamil United Front (later known as Tamil United Liberation Front), a pro-Tamil organization, is founded in Sri Lanka. May 26 Richard Nixon and Leonid Brezhnev sign the SALT I treaty in Moscow, as well as the Anti-Ballistic Missile Treaty and other agreements. Willandra National Park is established in Australia. May 27 – Mark Donohue wins the Indianapolis 500 in a Penske Racing McLaren–Offenhauser. May 30 Lod Airport massacre: Three Japanese Red Army members operating on behalf of the Popular Front for the Liberation of Palestine – External Operations kill 26 and injure 80 people at Lod Airport, Israel. The Troubles: The Official IRA declares a ceasefire. June June – Iraq nationalizes the Iraq Petroleum Company. June 3 – Sally Priesand becomes the first American woman (and the second known woman anywhere) to be ordained as a rabbi within Judaism. June 5–16 – The United Nations Conference on the Human Environment is held in Stockholm, Sweden June 8 Seven men and three women hijack a plane from Czechoslovakia to West Germany. Vietnam War: Associated Press photographer Nick