gender was determined by nurture, yet the patient, David Reimer, was deeply unhappy and had returned to his original gender by the age of 15, thus indicating the opposite thesis. March 16 – Sandline affair: On Bougainville Island, soldiers of commander Jerry Singirok arrest Tim Spicer and his mercenaries of the Sandline International. March 18 – The tail of a Russian An-24 charter plane breaks off while en route to Turkey, causing the plane to crash, killing all 50 on board, and resulting in the grounding of all An-24s. March 21 – In Zaire, Étienne Tshisekedi is appointed prime minister; he ejects supporters of Mobutu Sese Seko from his cabinet. March 22 – The Comet Hale–Bopp makes its closest approach to Earth. March 24 – The 69th Academy Awards, hosted by Billy Crystal, are held at the Shrine Auditorium in Los Angeles, with The English Patient winning Best Picture. During the event, the DVD format is launched in the United States. March 24 – 26 – In San Diego, 39 Heaven's Gate cultists commit mass suicide at their compound. March 26 – Julius Chan resigns as prime minister of Papua New Guinea, effectively ending the Sandline affair. April April 3 – The Thalit massacre in Algeria: all but 1 of the 53 inhabitants of Thalit are killed by guerrillas. April 14 Fire breaks out in a pilgrim camp on the Plain of Mena, from Mecca; 343 die. Former S.S. Captain Erich Priebke is retried; on July 22 he is sentenced to fifteen years in prison. April 18 – The Red River of the North breaks through dikes and floods Grand Forks, North Dakota, and East Grand Forks, Minnesota, causing US$2 billion in damage. April 21 – A Pegasus rocket carries the remains of 24 people into earth orbit, in the first space burial. April 22 Haouch Khemisti massacre: 93 villagers are killed in Algeria. A 126-day hostage crisis at the residence of the Japanese ambassador in Lima, Peru. April 23 – 42 villagers are killed in the Omaria massacre in Algeria. April 29 The Organisation for the Prohibition of Chemical Weapons (OPCW), CWC treaty enters into force. Two trains crash at Hunan, China; 126 are killed. May May 1 - Tony Blair becomes Prime Minister of the United Kingdom, as the Labour Party wins the 1997 United Kingdom general election and returns to government for the first time in 18