May 5, 1862 – Mexican troops under General Ignacio Zaragoza, outnumbered three to one, defeat the invading forces of Napoleon III in the battle of Pueblo which forever after is celebrated as a national holiday; Cinco de Mayo (Fifth of May).
May 5, 1961 – Alan Shepard becomes the first American in Space. His Freedom 7 spacecraft travelled in space for 15 minutes and 28 seconds. In a subsequent flight in 1971 he would become the fifth person to walk on the moon.
May 6, 1937 – The German airship Hindenburg bursts into flames and crashes while mooring at Lakehurst, New Jersey killing 36 of the 97 passengers and crew and effectively ending commercial airship travel.
May 7, 1915 – The passenger ship RMS Lusitania traveling from New York to Liverpool is torpedoed and sunk off the coast of Ireland by a German submarine with the loss of nearly 1,300 passengers, including 120 Americans. The sinking turns American sentiment against Germany leading up to U.S. entry in World War I in support of the Allies.