a civilian, are shot dead in Chicago. February 21 – In the first battle of the Warlord Rebellion in northeastern Shandong against the Nationalist government of China, a 24,000-strong rebel force led by Zhang Zongchang is defeated at Zhifu by 7,000 NRA troops. February 26 – Grand Teton National Park is established by the United States Congress. March March 2 – The longest bridge in the world at this time, the San Francisco Bay Toll-Bridge, opens. March 3 – A revolt by Generals José Gonzalo Escobar and Jesús María Aguirre fails in Mexico. March 4 Herbert Hoover is sworn in, as the 31st president of the United States. The National Revolutionary Party (Partido Nacional Revolucionario) is established in Mexico, by ex-President Plutarco Elías Calles. Under a succession of names, it will hold power in the country continuously for the next 71 years. March 17 – Second of the Davos University Conferences opens in Switzerland; this includes the Cassirer–Heidegger debate in philosophy. March 28 – Japanese forces withdraw from Shandong province to their garrison in Tsingtao, bringing an end to the Jinan Incident. March 30 – Imperial Airways begins operating the first commercial flights between London and Karachi. April April 3 – Persia signs the Litvinov Protocol. May May 1 – The 7.2 Kopet Dag earthquake shakes the Iran-Turkmenistan border region, with a maximum Mercalli intensity of IX (Violent), killing up to 3,800 and injuring 1,121. May 7 – "The Battle Of Blood Alley" is fought by a razor gang in Sydney, Australia. May 16 – The 1st Academy Awards are presented in a 15-minute ceremony at the Hollywood Roosevelt Hotel, honoring the best movies of 1927 and 1928, Wings (1927) winning Best Picture. Gerald Duffy (died 1928) receives the only Academy Award for Best Title Writing ever awarded (for his intertitles to the silent film The Private Life of Helen of Troy (1927)). May 31 – The United Kingdom general election again returns a hung parliament; the Liberals in Parliament determine which party will govern. June June 1 – The 1st Conference of the Communist Parties of Latin America is held in Buenos Aires. June 3 – The Treaty of Lima settles a border dispute between Peru and Chile. June 7 – The Lateran Treaty, making Vatican City a sovereign state, is ratified. June 8 – Ramsay MacDonald forms the United Kingdom's second Labour government. June 21 – An agreement