what historical events happened in the month of may?
['1st. 1st : 1931 The Empire State Building in New York Officially opens. ... ', '2nd. 2nd : 1930 Hoover Says Stock Market Crash Temporary Setback. ... ', '3rd. 3rd : 1926 General Strike is called for by the (TUC) in UK. ... ', '4th. 4th : 1886 Haymarket Square Riot Chicago. ... ', '5th. 5th : ... ', '6th. 6th : ... ', '7th. 7th : ... ', '8th. 8th :']